Product formulations must be designed for a specific body area. The first part in this series discussed skin care product design and selection considerations for the face, eyelids, and lips. These are unique areas with a high incidence of irritant and allergic contact dermatitis complicated by numerous interfaces with hair, oil glands, sweat glands, keratinized and mucosal surfaces. More products are available for the face than any other body area. Perhaps this is because the face is the most examined skin area and considered the essence of who and what we are to the external world.
Another important area of expression is the hand, providing the structures needed to write, draw, paint, dance, and express affection. It is frequently said that much can be said about a person from their handshake, which is an assessment of the skin, muscle, and bone that form the hand. The hand can express gender, occupation, and age. Female hands are small while male hands are large and muscular. People who work with their hands outdoors have a much different skin feel than persons who type on a computer for much of the day. Children have soft doughy padded hands while the elderly have thin sinewy bony arthritic hands. Hands are what make humans unique from every other living thing on the earth.
Skin care products designed for the hands are similar to those designed for the feet, since both structures contain the same basic skin anatomy. No discussion of the hands and feet would be complete without including the cuticles and the nails. Thus, part II of this three-part series focuses on formulations and skin care products for these specialized areas. Lip balms are not really designed for the hands and astringents are not designed for the feet!
The hands are formed of many tiny muscles and bones that account for their agility. They are that part of the body that most frequently touches the outside world and can serve as a vector, bringing infection to the vulnerable nose, eye, and mouth tissues. The hands also sustain considerable chemical and physical trauma. They are washed more than any other body area, yet are completely devoid of oil glands on the palmar surface.
While the stratum corneum of the palm is uniquely designed to withstand physical trauma, it is not designed to function optimally when wet. Water destroys the resistive physical strength of the palmar skin, which is why hand blisters are more common when the hand is perspiring heavily. The palmar surface of the hand has numerous sweat glands, known as eccrine glands, which are largely under emotional control. Palm sweating may occur in warm weather, but may also occur under stressful conditions.
The hand responds to trauma by forming a callus. Calluses are formed from retained layers of keratin that form a dead skin pad over the area subjected to repeated physical trauma. For example, the palm of the hand will callus to protect the small bones in persons who use a hammer. The finger will callus in the location where a pencil is held in both children and adults. While the body forms a callus to protect underlying tender tissues, the callus can also cause dermatologic problems. Since a callus is made of retained keratin, it is dehydrated and inflexible and will fissure readily with trauma. Once the keratin is fissured, it cannot be repaired, since the callus is nonliving.
Dermatologic disease needs to be divided into those conditions that affect the dorsum of the hand and those that affect the palm of the hand. This is an important distinction because the two skin surfaces are quite different. The dorsum of the hand is thinner skin that becomes increasingly thinner with age. After the face, the back of the hand is generally the most photoaged skin location. The skin of the hand looses its dermal strength early leading to decreased skin elasticity, which can be simply measured by pinching the skin on the back of the hand and watching for the amount of time it takes for the skin to rebound to its original conformation. Skin that takes a long time to return to normal configuration is more photoaged than youthful skin that bounces back energetically. In addition to losing elasticity, photoaged skin also becomes irregularly pigmented leading to lentigenes and idiopathic guttate hypomelanosis. This irregular pigmentation is also accompanied by skin that is easily injured exhibiting senile purpura, and tissue tears from minimal trauma, which heal with unattractive white scars.
The palm of the hand is affected uniquely by inflammatory conditions like eczema and palmar psoriasis. Because the palm is the surface that the body uses to pick and touch, it more commonly is affected by chemical and physical trauma. This trauma may manifest as hand eczema. Highly occlusive and emollient hand creams are necessary to rehydrate damaged keratin and create an optimal environment for barrier repair. Hand creams are also important in the treatment of psoriasis where too much poor quality skin is produced too quickly. Both of these conditions require carefully selected cleansers and moisturizers, in addition to prescription therapy.
Lastly, the palms can be affected by hyperhidrosis. Palmar hyperhidrosis can be physically disabling to persons such they cannot hold a pen to write or emotionally disabling such that they are uncomfortable shaking hands. As mentioned previously, the eccrine sweat glands on the palms are under temperature and emotional control. Palmar hyperhidrosis is usually more of an emotional condition, since the sweat released by the hands does little to cool the body.
The hands receive more cleansing than any other part of the body. The basic ritual of wash your hands before you eat is an effective method of preventing disease transmission, but may take its toll on the physiologically sebum lacking skin of the palms. Excessive hand washing can even be considered a medical disease, especially in persons with obsessive-compulsive disorder. There are a variety of methods of washing the hands. Basic hand washing is usually performed with a bar or liquid soap followed by water rinsing. Regimented timed hand washing routines are used to thoroughly remove all bacteria from the hands before surgery. Lastly, a variety of hand cleansing antibacterial gels have been introduced, usually based on triclosan, which can be used without water to clean the hands. In general, it is felt that the physical rubbing of the hands to lather the cleanser followed by rubbing in a running stream of water to rinse away the cleanser is important. Both the physical rubbing of the hands and the chemical interaction of the cleanser and water are necessary for optimal hand hygiene.
The skin care needs of the hands go beyond basic cleansing to moisturization, healing, photoprotection, and skin lightening. As mentioned previously, hand moisturization is very important due to frequent cleansing. Hand moisturizers should be designed to occlude the skin reducing transepidermal water loss, rehydrate the skin through the use of humectants, alleviate itch and pain, and smooth the skin surface with emollients. Hand moisturizers with this type of construction can be used for simple dry skin, as well as providing healing qualities for the dermatologic conditions previously discussed.
In addition to moisturization, the hands also need photoprotection both during sports and while driving a car, since photoaging UVA radiation passes through the windshield of a car. Sun protection is a unique challenge for the hands because they are frequently aggressively washed removing the sunscreen. However, the need for sun protection is obvious when one considers the thin dyspigmented skin that characterizes mature hands. This means that the hands require aggressive antiaging therapy and skin lightening.
The hands and the feet have much in common. They both have a different type of epithelium on the dorsal and plantar surface, they both have hair on the dorsal surface and none on the plantar surface, and they both have few sebaceous glands and numerous sweat glands on the plantar surface. However, there are many differences between the hands and the feet, the most important being that the feet constantly bear the weight of the body while the hands do not. The feet are used for locomotion, competitive athletics, and personal expression in the form of dance. They are forced into shoes that can function both as protection while walking and the source of bony deformity. One only need look at the bunions and overlapping toes of the woman who wore tall spiked heel pointed toe shoes during her youth who cannot walk normally today due to misshapen feet that cannot properly bear weight.
The feet form our most important point of contact between the body and the earth. They grow proportionately as we grow during adolescence, pregnancy, and old age to provide the body with stable balance. Unfortunately, their bones wear out with continued use and chronic inflammation to yield crippling arthritis. The sole of the foot is made of keratin remarkably resistant to trauma from torque and pressure, but this resiliency is decreased when the keratin is wet. This most commonly occurs in individuals with sweaty feet. The interaction of sweat with the plantar keratin in the environment of the shoe creates unique hygiene challenges. The lack of oil glands on the sole of the foot also predisposes to dry skin.
As might be expected, the warm moist dark environment of the foot in the shoe is perfect for infection of all types, especially between the toes. The foot is a common site for bacterial, fungal, and yeast infections. These organisms can live on the surface of the foot or enter into the body through small wounds. Foot infection is a major medical issue in diabetics who have a reduced capacity to fight infection, poor blood circulation to the feet, and reduced sensation. In normal individuals, the most common infection of the feet is tinea pedis. Mild infections of this type can occur in otherwise healthy athletic individuals, however the incidence of fungal infection increases with advancing age due to deterioration of the body’s immune system.
The foot is also a common site for eczema due to the complete lack of oil glands on the sole and the reduced number of oil glands on the top of the foot. The feet receive the most cleanser and water contact of any part of the body while showering, thus excessive removal of sebum on the feet is common. For all of the reasons put forth here, the feet have unique hygiene needs to balance the predilection for infection with the dryness of overcleansing.
The feet need aggressive hygiene, not only to prevent infection, but also to control odor. Foot odor is primarily due to the mixture of sweat with bacteria in the closed environment of the shoe. Bacteria digest the sweat to obtain nutrition and reproduce. Most individuals have several types of bacteria present in low numbers on the feet. The difference between individuals with minimal foot odor and extreme foot malodor is the number and type of bacteria present on the feet. Foot malodor is much greater problem in persons with hyperhidrosis. Hyperhidrosis of the feet is identical in cause to hyperhidrosis of the palms, in that both are primarily under emotional control, although feet tend to sweat more for thermoregulatory purposes due to the presence of warm socks and shoes.
Good cleansing of the feet is a prerequisite to skin health, but overly aggressive cleansing may set the stage for dry skin and foot eczema. Thus, foot cleansing must be carefully balanced with proper moisturization.
One way to minimize the dryness that may be associated with foot cleansing is with moisturizers. Moisturizers can be used to prevent foot dryness and soften calluses utilizing substances such as urea and lactic acid to open up water binding sites on dehydrated keratin. The physical act of rubbing a moisturizer on the feet can also help desquamate dead skin that may build up between the toes and on the arch of the foot, especially in elderly individuals. Foot moisturizers must be similar to hand moisturizers in that both occlusive and humectant substances must be incorporated.
No discussion of the hands and feet would be complete without consideration of the nails and cuticles. Even though the nails are made of nonliving keratin, they are the source of considerable cosmetic attention. Manicures, pedicures, artificial nails, nail polish application, etc. are all popular activities. Certainly, the nails add glamour and enhance the appearance of the hands and feet. In certain cultures, the fingernails even are used to designate class status. For example, Greek males allow their little fingernail to grow longer than the rest to show that they work at a desk job rather than performing manual labor, since a long little fingernail cannot be maintained if one uses their hands to make a living. Similarly, women in United States use long nails for much the same purpose. Since the nails are made of nonliving tissue, their cosmetic needs are much different than any of the other body areas previously discussed.
The nail is a thin plate of nonliving keratin designed to protect the tip of the finger and toes. The nail is produced by a group of cells designated as the nail matrix that lies approximately one-quarter inch below the visible nail. The nail matrix cells are formed at birth and cannot regenerate following injury. For this reason, trauma to the nail matrix can result in a permanently deformed nail that cannot repair and will not grow normally. One of the most important structures adjoining the nail from a dermatologic standpoint is the cuticle. The cuticle is a like a rubber gasket forming a watertight seal between the nonliving nail and the skin of the fingertip. Damage to the cuticle results in water, chemicals, or anything the hand touches reaching the nail matrix cells. It is for this reason that the cuticle not be dislodged, pushed back, trimmed, or manipulated in any way. Many of the abnormalities and diseases of the nail tissue can be traced back to a damaged cuticle.
Nail abnormalities and disease are extremely hard to treat because the visible nail cannot be repaired, only the growth of new nail influenced. In most individuals, it takes 6 months to grow a new fingernail and one year to grow a new toenail. This means that creation of a new nail to replace a damaged nail is a long process requiring patience before the effects of successful treatment are visible. The most common cosmetic nail problem is onycholysis. Onycholysis is usually traumatic in nature, more common in individuals who wear artificial nails in the form of sculptures or tips. The bond between the artificial nail and the natural nail is stronger than the bond between the natural nail and the underlying skin. This means that the natural nail plate will rip from the skin causing pain and swelling of the finger. The natural nail now appears white, because the nail is no longer attached to the pink flesh, and a space is created beneath the nail plate and the skin where infection can occur. Onycholysis is the most common condition predating a nail fungal infection.
Nail fungus is actually transmitted through fungal spores that extremely resistant to destruction. Traditional disinfectants used to clean manicure and pedicure instruments are ineffective against the spores, thus fungal disease can be transmitted through nail salons. Nail fungus is also not susceptible to triclosan or other antibacterial agents traditionally used in soaps and cleansers. Thus, the best protection against a nail fungus infection is an intact nail and surrounding cuticle.
Another common nail problem is peeling and cracking of the nail plate. While these are largely cosmetic concerns, they can result in pain and leave the nail weakened to infection. Nail peeling and cracking are more common with advancing age. This may be due to decrease blood flow to the cells of the nail matrix from arthritis or blood vessel disease or due to declining nutritional intake. The body certainly recognizes that the nails are not essential to maintain life, thus under times of stress or illness nail growth is not optimal. However, there are conditions where nutrients may not be absorbed from the intestinal tract that becomes more common with advancing age. One of these nutrients is biotin. Biotin is necessary for hard nails and may not be properly absorbed. For this reason, one of the main treatments for peeling, cracking nails is an oral biotin supplement. Nail dehydration may contribute as well.
As mentioned previously, the most important way to keep the nail plate healthy is to leave the cuticle undisturbed. For some, this answer is almost too simple. The nail is designed to take care of itself and any manipulation interferes the perfect design. Typically, hand hygiene and nail hygiene are taken care of simultaneously with good hand washing.
The most common infection that affects the nail is known as a paronychia. A paronychia is actually an infection of the skin surrounding the nail to include the cuticle. Here the cuticle is disrupted and water enters the tissue around the nail. This forms a warm, dark, moist space perfect for the growth of yeast organisms. The yeast breakdown the skin and make an environment appropriate for bacterial infection, which occurs secondarily. The bacteria then multiply and produce pain and pus. Use of antibacterial cleansers containing triclosan are very helpful in preventing a paronychial infection along with good moisturization of the tissues around the nail to prevent cracking.
Moisturizing the nail and the cuticle are important to prevent disease. Usually these structures are moisturized at the same time the hands are moisturized, but there are some key differences to consider. The outer stratum corneum layer of the skin of the hands is replaced every two weeks, but the nails are nonliving, thus any dehydration damage inflicted is permanent. Remoisturizing the nails can be minimally enhanced with urea and lactic acid, which increase the water binding sites on the nail keratin, but their effect is temporary until the next hand washing. Also, too much urea and lactic acid can over soften the nail plate making it more susceptible to fracture. Water is the main plasticizer of the nail plate and it should not be removed with aggressive cleansing.
Formulating and selecting products for the hands, feet, and nails is dependent on an understanding of the anatomy and physiology of the area, unique dermatoses, hygiene needs, and skin care needs.
As the resources of our earth are being stretched to limit with increasing global consumption, futurists are concerned about the impact many industries are exerting on the environment. Going green is certainly fashionable. It is easy to understand how cars contribute to pollution with the combustion of nonrenewable petroleum products. It is also easy to conceive of polluted ground water from toxic heavy metals leaching into the aquifer from 100-year-old landfills. It is a bigger reach, however, to determine how cosmetics could be environmentally hazardous.
The new trend in cosmetics is to include rare botanicalsto deliver some unique benefit, but also to allow the consumer to distinguish the brand from other competitors with marketing around a specific ingredient. An example of such a product is a $500 jar of face cream containing rare caviar obtained in the Caspain Sea from the beluga sturgeon during the natural birthing process. The caviar is supposed to be similar to human skin allowing amino acids to speed up collagen production. The only problem is beluga sturgeons are protected as part of the endangered species act. Harvesting the fish eggs is certainly damaging to this species.
Other ingredients found in cosmetics come from rare species, such as the red arctic tocol cranberry. This berry contains a complex rich in omega-3 fatty acids and vitamin E. It is said to increase the production of amino acids thereby enhancing skin repair and sold in a face cream for $470 per jar. Over harvesting these valuable berries could lead to extinction of the plant.
While fauna and flora are renewable resources on the earth, damage to their ecosystem and reproduction processes could interfere with this process. Issues associated with the continuation of species are termed sustainability issues. The skin care industry is very concerned with sustainability. How can ingredients be harvested without damaging the environment? Failure to answer this question may result in cosmetics that are environmentally hazardous.
Another controversial issue within the skin care industry is product packaging. What happens to the used plastic lipstick tube, the plastic empty powder compact, the depleted plastic shampoo bottle, and the clogged hand lotion dispenser plastic bottle? The answer is simple. All of these used plastic items are thrown in the trash and forgotten by the user, but the environment does not forget them. Alan Weisman, author of The World Without Us (Thomas Dunne Brooks/St. Martin’s Press), examines some of the pressing issues regarding plastic packaging. In his book, he discusses the work of marine biologist Richard Thompson who collected sand samples along the beaches of England in the 1980s. Thompson noticed a dramatic increase in small brightly colored plastic cylinders among the handfuls of sand he collected over the years. The cylinders, known as nurdles, are the raw the materials of plastic production and virtually indestructible. Further work by Alistair Hardy, another marine biologist, demonstrated an increase in nurdles in samples obtained 10 meters below the ocean surface. The work of these two scientists confirms that humans are filling up the oceans of the world with plastic packaging debris, some from old cosmetic tubes, bottles, and compacts.
While plastic packaging does appear to degrade with time, since plastic bottles are eventually broken down into small plastic fragments, it may lead us to believe that plastic waste is not much of a problem. However, the opposite is true. The degraded plastic is broken down into fragments that are indestructible, but can be ingested by marine life and animals. Weisman relates that 95% of fulmar bird carcasses washed ashore on North Sea coastlines had an average of 44 pieces of plastic in their stomachs. Thus, the degraded plastic particles may be more environmentally hazardous than the original plastic item. This concern has encouraged cosmetic companies, such as MAC, a division of Estee Lauder, to ask customers to return used cosmetic packaging for proper recycling.
Environmentally hazardous packaging is only part of the concern. Cosmetics that are washed down the drain into water reclamation plants are also under scrutiny. For example, a common ingredient in facial exfoliant scrubs is polyethylene beads. These beads roll over the skin surface in a liquid soap designed to remove sebum and desquamating corneocytes and are eventually washed down the drain. No problem? Wrong, these beads are tiny plastic spheres that do not degrade and could be an environmental hazard. This problem is not seen with ground jojoba seeds or walnut shells that biodegrade.
Ask the man on the street about substances that are environmentally hazardous. Chances are he will mention oil spills in the Artic Ocean, radioactive waste from spent nuclear power plant fuel, emissions from metal smelters, and automobile exhaust. The environmental hazards of cosmetics are probably not at the top of his list. Nevertheless, cosmetics are part of the green equation. Raw materials must be preserved and packaging must leave a small environmental footprint.
The male skin care market is rapidly expanding in the United States because of new product development and aggressive marketing tactics. Manufacturers see male skin care as a large area for economic growth as the female skin care market has shown sales for a number of years. Much of the interest in male skin care has focused on the concept of the “metrosexual” man. The metrosexual man is concerned with fashion, hair care, nail appearance, skin treatments, and cosmetic products. This image is in contrast to the “urban” man who is low maintenance and uses toothpaste, bar soap, mass-market shampoo, and shaving cream as the sum total of his products. The advertising push to popularize the metrosexual man is seen as a way to boost the sale of hair, skin, and nail care products and services by creating an image to which men of all ages can aspire.
The creation of the high maintenance “diva” female image by Coco Chanel and popularized by major cosmetic companies, clothing designers, and accessory manufacturers has boosted sales tremendously. Women of all ages, including prepubertal teenagers, feel the need to engage in such activities as nail painting, hair dyeing, eye adornment, and ear piercing to attain the media image of a beautiful woman. This perceived need by females has resulted in tremendous sales in multiple segments. Creating male purchasing opportunities similar to those available to females could conceivably double the economic potential of this category.
This then leads us to wonder whether male skin requires unique products. Is male and female skin that different? Could you take a female moisturizer, put it in a different bottle, and achieve the same result on a male face? This article examines the unique issues differentiating male and female skin care.
It is said that the skin of women is made of sugar and spice and everything nice while snips and snails and puppy dog has characterized the skin of men tails. From a dermatologic perspective, this is an oversimplification. The differences between the skin of males and females are obvious to the human eye. Male skin is thicker than female skin, in part due to the presence of terminal hair follicles over much of the body. This difference is most pronounced on the face where women have only vellus hairs, which are fine and colorless, while men have fully developed terminal hairs, which are coarse and pigmented, taking up space within the skin. The presence of male facial hair is partially responsible for the more favorable appearance of mature men over mature women. As UV radiation activates collagenase to destroy dermal collagen, the male beard allows the skin to resist wrinkling. Thus, photoaged males do not exhibit the pronounced redundant facial skin seen in photoaged females.
The male beard also gives the skin the ability to camouflage surface cosmetic irregularities, such as scarring. If the beard containing skin of the male face is stretched, hypopigmented depressed acne scars may become apparent. The beard stubble also provides skin color irregularity, which camouflages telangectasias on the lower cheeks. In summary, the male face has a coarse appearance, which is considered masculine and desirable, as opposed to the female face that must be even in texture and color. Thus, women are more preoccupied with “fixing” problems than men who do not see skin changes as easily or as early in life.
The most basic skin care need is facial cleansing. Most men wash their face twice daily with bar soap. Why have men been satisfied with bar cleansers and not purchased more pricey facial cleansers like their female counterparts? Because bar cleansers works quite well on the average male face. Males have more sebum, eccrine sweat, and apocrine sweat than females and the excellent cleansing offered by bar cleansers meets their hygiene needs. Males also have the need to control odor, since bacteria degrade the apocrine sweat, which mixes with sebum to create a characteristic musty smell.
The most popular male cleansers are known as combars, a contraction of combination bars, which contain synthetic detergent cleansers, a small amount of soap, and usually antibacterial agents. The most popular antibacterial is triclosan, also found in antibacterial waterless hand sanitizers. Triclosan interferes with formation of the bacterial cell wall effectively reducing the bacterial degradation of apocrine sweat. Female facial cleansers typically cover body odor by adding a fragrance, rather than incorporating an antibacterial. They also do not remove sebum as thoroughly as male facial cleansers, since men like a tight skin feel after cleansing while women, who are sensitive to skin scale flakes disrupting smooth cosmetic application, like a softer facial feel.
The one new development that may change the male skin care market more than ever is effective laser hair removal. Some men are electing to permanently remove facial hair, which creates hygiene needs more aligned with female skin care. This needs to the consideration in male skin care, which is shaving.
While laser hair removal for men is gaining in popularity, most men still consider facial hair and important part of their masculinity. The razor market is well ahead of the skin care market in developing products specifically for men. Shaving has an important impact on male facial skin care. It is probably the most effective physical method of exfoliation, better than topical hydroxy acids or hand held microdermabrasion devices or mechanical brushes. It efficiently removes desquamating corneocytes along with beard debris obviating the need for facials and other spa procedures. Shaving is also an effective method of removing comedones from the skin, providing acne treatment.
However, improper shaving techniques result in razor burn and pseudofolliculitis barbae. Razor burn results from the removal of the skin around where the hair exits, an opening known as the follicular ostia. Newer razors with a flat to the skin design and multiple spring-mounted blades decrease razor burn. The flat razor design minimizes the need to keep the razor at a certain angle to avoid cutting the skin. It is easiest to maintain a steady angle when the flat razor can glide over the skin surface, requiring less manual dexterity. The multiple blades provide a closer shave without pressing the razor in the skin. The first blade lifts the hair from the skin and each successive blade cuts the hair closer and closer to the skin surface.
The success of a shave can also be improved by selecting a shaving gel. The post forming shaving gels, which are dispensed as a gel and then rubbed into the skin to form a foam, enhance the absorption of water into the hair, softening the protein bonds in the hair and decreasing the force required to cut the hair. It is said that a dry hair shaft has the same resistance to cutting as a similar diameter copper wire. The shave gel reduces razor burn and pseudofolliculitis barbae, seen in individuals with kinky facial hair where the sharp edge of the cut hair re-enters the skin, by decreasing skin friction and improving the closeness of the shave.
Shaving is usually the final male grooming activity, which is different from females who usually apply a facial moisturizer after cleansing. Why do most men not apply a moisturizer? Because male facial sebum production is typically high, obviating the need to moisturize. Most men do not need to retard transepidermal water loss because they do not expose their skin to the number of products used by females, they do not engage in multiple barrier damaging procedures, and their rapid sebum replacement is adequate. Men typically need emollients, rather than moisturizers, unless skin disease is present that smooth down the desquamating corneocytes by filling in the intercellular spaces where lipids may have been removed from over aggressive cleansing. The most popular emollient is dimethicone, which may be delivered to the skin surface in the form of a toner, aftershave lotion, skin bracer, etc. This is a key difference in products developed for males and females.
Female moisturizers are typically more occlusive to increase skin hydration and minimize periorbital wrinkling due to dehydration. These fine periorbital wrinkles are seen as signs of aging in women, but appear to contribute to character in males. Thus, antiaging moisturizers have been slow to catch on in the male skin care market. While women are eager at a young age to engage in the purchase of wrinkle creams, men are more resistant. The rugged coarse look is valued as a sign of masculinity and maturity. The thicker male skin is also less able to respond to beneficial effects of moisturization, especially on the hair bearing upper cheeks. Wrinkle creams simply do not have early appeal to men due to their perceived lack of need and poor immediate efficacy.
Some of the resistance of male skin to aging is due to the photoprotection afforded by facial hair. The follicle also increases skin thickness, decreasing the penetration of UVA radiation into male skin. This allows women to age more rapidly than men, a phenomenon magnified by the media preference for younger leading women paired with older leading men. Thus, men do not see the need for the application of sun protection to same degree as their female counterparts.
Male skin care is similar, but different, from female skin care. The presence of the facial beard provides photoprotection and resistance to facial wrinkling, but hair removal can be challenging. Shaving can improve skin texture and minimize acne, but poor shaving techniques can cause razor burn and aggravate pseudofolliculitis barbae.
The unique male biofilm, composed of apocrine sweat and sebum, requires different hygiene needs. It is not enough to package male skin care products in blue bottles and female skin care products in pink bottles. The material inside the bottle must cater to the unique skin needs of the different sexes.
Is all skin alike? This is a simple question with a rather complex answer. The simplest answer to this question is to focus on the differences in skin pigmentation, due to the distribution of melanin and the architecture of the melanosomes. Probably the most extensive analysis of skin color has been undertaken by companies that manufacture facial foundations. Facial foundation is the one cosmetic that must match each and every color of skin. For Caucasian skin, it takes appropriately 8 shades to match the range of skin color, which varies from tones of light tan with orange to yellow to pink undertones. For African-American skin, it takes approximately 28-33 shades to accurately match the tremendous range of skin color. Most companies do not manufacture this many colors, because they are trying to blend skin color rather than to add skin color, yet the color variation is tremendous. African-American skin can range from mahogany to blue black to light honey brown to dark black brown, etc. The skin colors found in persons of Mediterranean, Middle Eastern, Asian, and Hispanic background requires more than 8 shades, but less than 33. There are no cosmetic lines designed specifically for these racial groups so data is harder to obtain, but I suspect that 10-12 shades would cover each of these groups. Basically, the more racially mixed a group of people become, the more diverse the skin colors within the self-identified ethnic group.
Yet, there appear to be more differences than just pure skin color. Much has been said about the different dermatologic diseases and disease presentations that afflict each ethnic group. Persons with Caucasian skin are more concerned with redness and flushing, which is clearly less common among the darker skin types. It appears that this enhanced ability to flush also predisposes to rosacea, a condition quite rare among African-American individuals. Hispanic and Asian individuals seem to be more afflicted with skin pigmentation disorders, such as melasma associated with the use of oral contraceptives. African-American persons seem to present with eczematous conditions that tend to follow a more follicular pattern than the traditional plaques found in Caucasians. Certainly, these observations seem to point to something inherently different in skin between these ethnic groups.
In order to answer the initial question posed at the beginning of this article, I decided to do a literature search on the articles written about comparative skin physiology. I have organized the information in Table 1. Certainly these observations are generalizations, yet they may be helpful to understand the reported differences between skin of various ethnic groups with attention also to the changed that occur with mature skin.
Stratum corneum thickness is an interesting parameter to evaluate, since it may correlate with skin barrier function. The stratum corneum appears to be thicker in Caucasian skin at 7.2 microns compared to 6.5 microns in Black skin. Yet, data also exists to show that there are more corneocyte layers in Black skin at 22 as compared to the 17 layers found in Caucasian skin. Some persons theorize that the thinner stratum corneum observed in Black skin makes it more sensitive. Nevertheless, the stratum corneum in all aged skin, regardless of ethnic background, becomes thinner. Mature skin does not necessarily demonstrate increased sensitivity, however. If anything, mature skin appears to be less easily irritated. This decrease in irritation is probably due to decrease immune responsive which takes precedence over stratum corneum thickness.
TEWL is another method of assessing barrier function apart from the physical characteristics of the stratum corneum. TEWL is a measurement of the water that is being lost from the skin. As one might imagine, skin that is afflicted with a dermatitis looses more water while healthy intact skin looses less. For experimental purposes, the stratum corneum may be degraded by either chemical or physical means to observe the change in TEWL. The most common method of chemical stratum corneum degradation is the application of sodium lauryl sulfate (SLS) to the skin surface. SLS is a strong surfactant that removes the intercellular lipids causing barrier compromise. It appears that both Hispanic and Black skin are more susceptible to SLS damage than Caucasian skin. The physical method of degrading skin is tape stripping where by adhesive laden tape is repeatedly applied to the skin surface to physically remove the stratum corneum layer by layer. Data available from tape stripping of Asian and Black skin indicates increased TEWL over Caucasian skin. Do these findings account for the increased sensitivity self perceived by Asian, Black, and Hispanic individuals? It cannot be definitely stated since there are other factors besides TEWL that influence sensitive skin.
It is interesting to note that mature healthy skin demonstrates less TEWL than younger healthy skin. This finding seems to go against the observable prominent flaking seen on the shins of mature individuals. Even though this skin appears dry, it is not loosing excessive amounts of water to the environment. In some aged persons, it may be that the appearance of dry skin is due to the inability of corneocytes to slough rather than premature sloughing due to xerosis or xerotic eczema.
Another assessment of the barrier function of the skin is corticosteroid penetration. Corticosteroid penetration is more in Caucasian skin and less in Black skin. This does not appear to be consistent with the thicker stratum corneum in Caucasians and the thinner stratum corneum in Black skin. However, it could be that the Caucasian skin demonstrates the vasoconstriction associated with corticosteroids to a greater degree than Black skin, the next topic of discussion.
As might be expected due to the increased incidence of rosacea in Caucasian individuals, there is more blood vessel reactivity in Caucasian skin. The blood vessel reactivity is the same in Hispanic skin, but less in Black skin, which does not appear to be age related.
One method of assessing irritation is blood vessel reactivity, but others include the development of post-inflammatory hyperpigmentation and the subjective perception of stinging. While erythema is the primary response to irritation in Caucasian skin, the more deeply pigmented Hispanic and Black skin respond with pigmentation and erythema. Interestingly, the response to pigmentation in mature skin is decreased, probably due to the decreased melanization seen in this age group.
Previously we have discussed the differences in skin function, but there is also literature to support structural differences, such as the increased number of apocrine and eccrine sweat glands in Black individuals over Caucasian individuals. I am not aware of any studies, however, documenting an increased incidence of hyperhidrosis in one ethnic group over another.
The last assessment I found in the literature had to do with differences in ceramides, one of the building blocks of the intercellular lipids providing for maintenance of the skin barrier. Ceramides appear to be highest in Asian individuals followed by Hispanic individuals and Caucasian individuals with the lowest ceramide concentration in Black individuals. Ceramide concentration is the lowest in mature individuals.
Studies demonstrating the differences between the various ethnic groups may be considered to be somewhat academic in nature. They may or may not reflect the actual conditions observed in a dermatologist's office. Certainly, these studies are taking the "lumping" rather than the "splitting" approach to dermatologic assessment. There are some conflicting studies in the literature, which further complicate the issue of assessing skin differences. I opened this discussion with the question of whether all skin is alike. It is probable that all skin is not alike, but gleaning useful information from the differences may be difficult.
A significant change has occurred in the US during the last 10 to 15 years as a broad swath of the population has embraced at least some aspect of complementary and alternative medicine (CAM). Within this framework, the use of herbal therapies is the most pertinent to dermatology. This is particularly true since herbal therapies are said to represent the most common CAM modality used by adults in the US. Botanicals with long-standing uses in traditional or folk medicine are especially popular. Several of the copious supply of herbal ingredients under investigation for their potential medical benefits, or those established through research to exhibit such activity, are touted for imparting dermatologic benefits and various topical formulations have become available to join the more numerous array of oral botanical supplements. This discussion will focus on selected herbal ingredients many of which have gained increasing attention in the West after much longer use in Asia and that are used in cosmeceutical products intended for dermatologic purposes, including: Angelica, calendula, curcumin, garlic, ginger, ginkgo biloba, ginseng, silymarin, soy, and tea tree oil. Other products of botanical origin that have gained more mainstream appeal, and use within the medical establishment, such as arnica, bromelain, green tea, licochalcone (licorice), curcumin, ferulic acid, resveratrol, caffeine, and pomegranate are also briefly considered.
Various angelica species have been used in traditional or folk medicine since ancient times. In particular, for more than 1,000 years, the fragrant perennial plant Angelica sinensis, better known as dong quai, has been used for medicinal purposes in China, Japan, and Korea, most often as a traditional treatment for dysmenorrhea, amenorrhea, menopause, and related conditions for women’s health.1 Although such uses have not been established in conventional Western medicine,1,2 evidence is mounting to suggest that A. sinensis displays anti-carcinogenic and antioxidant activity. In fact, the potent antioxidant ferulic acid has been identified as a major active constituent in A. sinensis.3 In addition, antioxidant activities were concentration-dependently exhibited in a study evaluating the antioxidant activities of aqueous extracts of A. sinensis, Lycium barbarum, and Poria cocos, three herbs often used in Traditional Chinese Medicine (TCM).4 Further, the total polysaccharide from A. sinensis has been demonstrated to impart anti-tumor effects on in vivo murine models.5
More pertinent to potential dermatologic application is recent data suggesting that A. sinensis has been shown to significantly facilitate melanocytic proliferation, which substantially improved cell counts, and to promote melanin synthesis and melanocytic tyrosinase activity. Investigators who made these observations concluded that such a mechanism may warrant the use of A. sinensis for the treatment of skin dyschromias.6 Notably, a TCM formula called Si-Wu-Tang (SWT) that is used to treat cutaneous pruritus, chronic inflammation, and other conditions contains A. sinensis.7 A. sinensis taken in high doses may raise susceptibility to photosensitivity reactions, so patients on such doses should be especially discouraged from sun exposure. Also, A. sinensis is contraindicated for patients on warfarin.8,9
Two chalcone derivatives from Angelica keiskei roots have been found to inhibit tumor growth and metastasis by suppressing tumor-induced neovascularization and/or reducing the immune suppression brought on by tumors.10 In addition, chalcone extracts of the root of A. keiskei, also known as “Ashita-Ba,” which is consumed as a vegetable in Japan, have also displayed anti-tumorigenic activity in the two-phase mouse skin cancer model.11 Another angelica species, Angelica acutiloba, which is a primary ingredient in the Japanese drug Shi-un-kou, has exhibited significant inhibitory activity against skin tumor formation in an in vivo examination with mice.12
A decade ago, the Kampo (Japanese herbal medicine based on Chinese methods) oral medication Keigai-rengyo-to (TJ-50), which contains A. archangelica root among 16 other herbs, was found to significantly and dose-dependently reduce reactive oxygen species.13 In addition, Propionibacterium acnes has also exhibited notable sensitivity to Keigai-rengyo-to in vitro.14 A. archangelica is an important ingredient, along with borage seed oil, evening primrose oil, ascorbyl palmitate, and alpha tocopherol, in Zestra for Women, a topical botanical formulation intended to enhance female sexual pleasure and arousal. The oil of A. archangelica is also used in combination with other ingredients in perfumes, salves, shampoos, and soaps.
A. gigas is a key component in a formulation also containing Synurus deltoids and glucosamine sulfate that has been shown to dose-dependently inhibit ear edema in mice and is thought to have potential as a neutraceutical therapy for inflammatory conditions.15 A. dahurica, which has been used traditionally to treat psoriasis and for reputed antihistamine effects, was found in a recent study of herbs used in traditional Chinese and Japanese medicine to treat acne to significantly inhibit neutrophil chemotaxis, comparable to erythromycin (0.01%).16 A. dahurica and A. pubescens have also been found to inhibit elastase in intact leukocytes and platelets.17,18 Previously, A. pubescens had been shown to impart analgesic and anti-inflammatory effects.19
Calendula officinali,s also known as pot marigold or garden marigold among other names, belongs to the Compositae or Asteraceae family, which includes daisies, arnica, chamomile, and yarrow, known to possess antibacterial, anti-inflammatory, and antioxidant properties, was used in ancient Rome, for breaking fevers. A study with mice has shown significant anti-inflammatory evidence exhibited by several members of the Compositae family, including calendula.20 Naturopathic healers recommend topical calendula as an external wash, for ocular inflammations, abscesses, acne, bee stings, boils, eczema, and varicose veins. In various forms, calendula extracts are believed to be useful in wart removal, as a vaginal douche, a topical hemorrhoid treatment, and treating diaper rash as well as nipples sore from breastfeeding. Among homeopathic practitioners, calendula is considered a suitable home remedy for treating scrapes and burns.21 In Western medicine, calendula has been used as an antiseptic and anti-inflammatory agent, treating some skin disorders and pain,22 and is included in nearly 200 cosmetic formulations representing a vast range of product types.23
Triterpenoids appear to be the most significant anti-inflammatory constituents of calendula.24 In addition, the concentrations of flavonoids and carotenoids, such as lutein and lycopene, in calendula, are thought to contribute to its antioxidant effect. Although calendula is generally considered safe, allergic response is possible. In addition, despite a growing body of research on the use of calendula, current data are not sufficient to establish a scientific standard of safety for Calendula officinalis extract in cosmetic formulations.23
Turmeric (Curcuma longa, Zingiberaceae) is best known as a spice used primarily in Asian cuisine, particularly curry, and in prepared mustard. But it is also used in some traditional Indian communities as a topical burn treatment.25 In fact, turmeric has long been used as an anti-inflammatory agent in Chinese and Ayurvedic medicine.26 Specifically, turmeric has been used in Ayurvedic medicine to treat sprains and edema due to injury.27,28
Curcumin (Diferuloylmethane), the key biologically active component of turmeric, has shown great potency against acute inflammation,26 and has been shown to exhibit significant wound-healing, anticarcinogenic, anti-inflammatory, and antioxidant properties.29 Its anticarcinogenic characteristics are particularly well documented,30-32 as are its demonstrated antioxidant and lipid peroxidation activity.29,33-36 Antibacterial, antiparasitic, and anti-HIV activity has also reportedly been exhibited by turmeric or curcumin.37 And curcumin reportedly has greater anti-inflammatory capacity than ibuprofen.26
In various animal models, topical application of curcumin has been shown to inhibit initiation and promotion of tumorigenesis.38-42 In addition, very low doses of topically applied curcumin have been found to mediate TPA-induced oxidation of DNA bases in the epidermis and tumor promotion in the skin.43 Pretreatment with curcumin has exhibited the same inhibitory effects on TPA-mediated dermatitis.44,45 Finally, topical curcumin is considered one of the only safe therapies for radiation exposure,25 and it is believed to possess great potential as a therapeutic agent for wound repair, especially in reducing healing delays caused by radiation and involving combined injuries.46 Cosmetics containing curcumin are available throughout the world, particularly in India.44
In TCM, garlic (Allium sativum) is believed to act against Staphylococcus aureus, Bacillus dysenteriae and other bacteria.47 Throughout human history, garlic has been used to treat various age-related conditions.48 It was also considered an effective remedy for tumors as far back as ancient Egypt more than 3,000 years ago.49 During the last 15 years, this aromatic herb has developed a noted reputation for its potent antioxidant properties48 and capacity to inhibit chemically-induced mouse skin carcinogenesis50-54 as well as its capacity to prevent or delay age-related diseases.48 Recent studies have suggested that garlic, as well as onion, oils may inhibit skin tumor promotion by enhancing the natural glutathione peroxidase-dependent antioxidant-protective system of epidermal cells.44,55
The primary components of garlic have also been isolated and found to exhibit significant salutary effects. Diallyl disulfide (DADS) is a low molecular weight garlic ingredient,56 and one of its main components that is characterized by chemopreventive activity against human colon, lung, and skin cancers.44,57-59 Diallyl sulfide (DAS), a volatile organosulfur compound and a major flavor component in garlic,60 has been shown to exhibit anticarcinogenic effects in various rodent tumor models.50,61-62 In addition, the topical application of the garlic constituent ajoene (4,5,9-trithiadodeca-1,6,11-triene-9-oxide) has yielded significant clinical response in patients with skin basal cell carcinoma, specifically reducing tumor size.49,63 Ajoene applied as a 0.4% (w/w) cream has also been effective as a short-term treatment for tinea pedis.64 Its efficacy in treating cardiovascular diseases and fungal infections is now considered established.49,63
Long considered a universal remedy, ginger, Zingiber officinale, has been used as a traditional herb for over 5,000 years. Ginger has a reputation as one of the most effective herbal remedies for nausea and is also touted for its anti-viral, anti-fungal, and anti-bacterial properties.65,66 It is thought to be effective against the growth of both Gram-positive and Gram-negative microbes. A study on SENCAR mice has shown that ginger extracts exhibit antioxidant, anti-inflammatory and anticarcinogenic activity. Ginger oil topically applied on the skin of mice prevented skin cancer development or growth after the mice were exposed to chemicals that promote cancer.67
The component most responsible for inhibiting tumor activity in murine skin cancer has been identified as the pungent phenolic substance -paradol. Other structurally related derivatives have also been shown to induce apoptosis through a mechanism dependent on caspase-3.68 Both -paradol and the structurally related -gingerol have been shown to inhibit epidermal growth factor (EGF)-induced cell transformation.69 In addition, the methanolic extract of Alpinia oxyphylla Miquel, a member of the ginger family (Zingiberaceae), has been found to suppress mouse skin tumor promotion and to induce apoptosis in cultured human promyelocytic leukemia cells.70 Currently, ginger oil is often included in mouthwashes and perfumes, especially men’s colognes. Ginger oil is also occasionally used in the treatment of varicose veins due to a purported capacity to enhance circulation.
In China and Japan, the leaves and nuts of the Ginkgo biloba tree have been used for thousands of years to treat various medical conditions, including poor circulation; hypertension; poor memory, dementia, and depression, particularly among the aged; male impotence; and disorders related to an inner ear imbalance, such as deafness, tinnitus, and vertigo.71 In addition, Ginkgo biloba is gaining a similar reputation as a significant antioxidant and anti-inflammatory agent.72-74 The G. biloba extract EGb 761, prepared from the tree’s leaves, is a natural mixture containing flavone glycosides (33%), mostly quercetin and kaempferol derivatives, and terpenes (6%), that has exhibited the capacity to reduce the number of UVB-induced sunburn cells in mice.75
In a double-blind placebo-controlled trial in which 47 patients were evaluated, investigators assessed the efficacy of G. biloba extract in controlling limited and slow-spreading vitiligo and promoting repigmentation in affected areas. One group of patients was administered 40 mg G. biloba extract three times daily and the other group received the same doses of placebo. Researchers observed a statistically significant cessation of depigmentation in patients treated with G. biloba, with notable to complete repigmentation seen in 10 patients from the treated group, but only two patients in the placebo group. This study lends support to the notion that G. biloba extract may be an effective, safe approach to arresting the progression of vitiligo.76 In addition, a decade ago, Ginkgo extracts, including the flavonoid components quercetin, kaempferol, sciadopitysin, ginkgetin, and isoginkgetin, were shown to enhance the proliferation of normal human skin fibroblasts in vitro and additional assays of fibroblasts incubated with G. biloba extracts and ascorbic acid and controls incubated only with ascorbic acid showed increased collagen and extracellular fibronectin synthesis in the treatment group.77
Several varieties of ginseng have been used in traditional medicine by several cultures, in Asia and Native America in particular, for thousands of years. Western medicine has come to recognize that ginseng is associated with anti-inflammatory, antioxidant, and anticancer activity.78 In fact, the more-often-studied major active components of ginseng, ginsenosides, are known to exhibit anti-aging, anti-oxidant, and anti-inflammatory activities.78-80 In addition, the risk of cancer has been shown in epidemiological studies to be reduced by the consumption of ginseng,81 as several species of this traditionally used herb have become associated with significant anticarcinogenic activity.82-86 Overall, ginseng has been associated with an increasingly diverse list of conditions for which it might be indicated.
An in vivo mouse skin study of the effects of IH-901 [20-O-beta-d-glucopyranosyl-20(S)-protopanaxadiol (also known as compound K), an intestinal bacterial metabolite derived from protopanaxadiol-type saponins of Panax ginseng] has shown the ginseng byproduct to be effective in conferring anti-inflammatory effects that may be conducive to the overall anti-tumor activity displayed by ginseng in mouse skin.81 In addition, topically applied compound K has been found to have significant dermatologic potential, as it appears to have the capacity to prevent or reverse symptoms associated with the age-related decline of hyaluronan levels in human skin (e.g., xerosis and wrinkles).79 Other ginsenosides have exhibited the potential capacity to promote wound healing87 and hair growth,88,89 and to treat pruritus.90 Ginsenoside F1, an enzymatically modified derivative of ginsenoside Rg1, has been shown to exhibit protective activity against ultraviolet-B-induced damage in human HaCaT keratinocytes.80 Finally, in an in vitro study evaluating the effects of Radix Ginseng (RG) and Radix Trichosanthis (RT) on melanogenesis in B16 melanoma cells, researchers found that treatment with RG and RT together significantly inhibited melanogenesis in B16 cells, and that this combination may be effective as a depigmenting or whitening agent for the skin.91
Silymarin is a naturally occurring polyphenolic flavonoid compound or flavonolignans antioxidant derived from the seeds of the milk thistle plant Silybum marianum,92-94 which has been used for over 2,000 years for various medical purposes.95 Today, it is used clinically in Europe and Asia as an antihepatotoxic agent,96-98 and is available as a supplement in Europe and the US.98 The main constituent of silymarin by volume (70-80%) is silybin, which is considered its most biologically active component in terms of antioxidant, anti-inflammatory,92,95,99 and anticarcinogenic properties.100
While the antioxidant activity of silymarin is considered to be established, its potential chemoprotective activity against skin cancer has been reported and is under investigation.93,101 Topically applied silymarin has demonstrated strong inhibitory activity toward benzoyl peroxide-induced skin edema, myeloperoxidase activity, and interleukin-1alpha protein levels in the epidermis, buttressing the argument that silymarin exhibits significant anticarcinogenic potential.102 Indeed, some authors speculate that silymarin, and/or its major active constituent silybin, has the potential to prevent and retard human skin cancer,103 and may warrant inclusion in sunscreens and consideration in the armamentarium against skin cancer and other human cancers of epithelial origin.93,104 In fact, topically applied silymarin has been associated with significant inhibition of UVB-induced sunburn, apoptotic cell formation, and edema.94,96
The topical use of soy has been touted to ameliorate hyperpigmentation, enhance skin elasticity, delay hair regrowth, control oil production, and moisturize the skin. It is also thought by some to have the potential to decrease skin aging and prevent skin cancers through the estrogen-type and antioxidant effects of its metabolites. Small proteins such as soybean trypsin inhibitor (STI) and Bowman-Birk inhibitor (BBI) have been suggested to inhibit skin pigmentation, while large proteins have been found to smooth and soften the skin. STI, BBI, and soy milk have been found not only to exhibit depigmenting activity but also to prevent UV-induced pigmentation in vitro and in vivo; specifically, STI and BBI are thought to influence melanosome transfer, thus pigmentation.105 Because soy exerts some estrogen-type effects and melasma is somewhat estrogen mediated, soy use in patients with melasma is not recommended.
The primary metabolites of soy isoflavones, genistein and diadzein, have been identified in various studies in animal and human cell cultures as phytoestrogens, which are plant compounds with a weak estrogenic effect.106 Several studies have shown that postmenopausal women have a measurably thinner dermis and less collagen as compared to premenopausal women. Topical estrogen has been demonstrated to retard the skin thinning and collagen loss seen in postmenopausal patients not on hormone replacement therapy, likely because estrogen receptor levels are highest in the granular layer of the skin. Therefore, the phytoestrogens genistein and diadzein have the potential to confer beneficial cutaneous effects, though this has not yet been established. Genistein has been shown, though, to significantly inhibit chemical carcinogen-induced reactive oxygen species, oxidative DNA damage, and protooncogene expression, as well as the initiation and promotion of skin carcinogenesis in mouse skin, and to potently inhibit UVB-induced erythema in human skin.107 Patients at high risk for or with a history of estrogen-sensitive tumors, such as breast or uterine cancer, should avoid using soy.
Derived from the Australian Melaleuca alternifolia, tea tree oil (TTO) has been used for centuries by indigenous people in Australia as an herbal medicine and long regarded as an effective topical antiseptic and broad-spectrum antimicrobial agent. In recent years, this essential oil has been used for indications including acne, psoriasis, fungal infections, vaginal infections, tinea, lice, rashes, cold sores, cuts, scratches, various burns (including sunburns), and for dental applications. TTO has been incorporated into antifungal formulations in soaps and shampoos, dental products (e.g., mouthwashes, toothpastes), veterinary products (to ward off fleas and ticks), and various household and industrial disinfectants. Other potential applications include use as a laundry detergent ingredient (to eliminate mites) and as an antioxidant, though one study suggests that TTO lacks antioxidant activity.108 Regardless, some components of TTO may alleviate hypersensitivity reactions. In one study, two components of topical TTO, terpinen-4-ol and alpha-terpineol, were found to regulate the edema associated with the efferent phase of a contact hypersensitivity reaction.109 Terpninen-4-ol was also found, in a study by the same team, to be effective in controlling the histamine-induced edema often linked to Type I allergic reactions.110
In an often-cited TTO study by Bassett et al., both 5% tea tree oil and 5% benzoyl peroxide exhibited significant effects in improving patients’ acne by reducing the number of inflamed lesions, both open and closed comedones. Although the onset of action of tea tree oil was slower, patients treated with tea tree oil experienced fewer side effects.111 TTO is considered safe for use by most patients and its broad-spectrum antimicrobial activity has been acknowledged with increasing frequency in the literature.112,113 The effectiveness of lipophilic TTO in blocking the conversion of Candida albicans from the yeast to the pathogenic mycelial form in one study suggested, according to the authors, that TTO may be an appropriate agent for treating fungal mucosal and cutaneous infections.114
Arnica montana has recently become popular as a topical treatment to improve inflammatory skin conditions, reduce bruising, and heal chronic wounds. Recently, patients in a double-blind study taking perioperative homeopathic A. montana exhibited less ecchymosis than the placebo group after undergoing rhytidectomy.115 The anecdotal experience of the author suggests that arnica accelerates bruises healing and topical arnica is recommended to patients after soft tissue augmentation, Botox (botulinum toxin) injections, fat transfer, and liposuction.
Bromelain, the family of sulfhydryl-containing proteolytic enzymes derived from the stem of the pineapple plant, Ananas comosus,116 is most often used to treat inflammation and soft tissue injuries, as well as to aid digestion. Its proteolytic enzymes have been shown to promote wound-healing,117 reducing edema, bruising, and pain, and pre-surgical administration is associated with accelerated healing after trauma and surgical procedures.118
German chamomile (Matricaria recutita or Chamomilla recutita), one of the 12 most commonly used medicinal herbs,119 has been recognized for its therapeutic, soothing properties since the age of Hippocrates. Chamomile is thought to impart significant cutaneous benefits, such as improving texture and elasticity, as well as reducing pruritus and signs of photodamage, and chemical assays have suggested that chamomile exhibits some antioxidant activity.120 Chamomile is included in skin formulations as an emollient and to provide anti-inflammatory action for sensitive skin.
The pomegranate plant (Punica granatum) appears to offer numerous dermatologic uses. Pomegranate seed oil has been demonstrated to exhibit chemopreventive activity against skin cancer.121 Pomegranate extract has antioxidant and antiviral properties and is said to enhance the effectiveness of topical sunscreens. Pomegranate juice is believed to be a much more potent antioxidant than comparable quantities of green tea and red wine.122 In addition, pomegranate peel fractions may foster dermal regeneration and pomegranate seed oil fractions may facilitate epidermal regeneration.123 Finally, pomegranate fruit extract has been identified as an effective photochemopreventive agent.124,125
Caffeine, consumed in popular beverages such as coffee and tea, as well as in certain foods, is thought to have significant anti-carcinogenic and antioxidant properties. Specifically, caffeine is believed to confer an anticarcinogenic effect after UVB exposure, chemically inducing apoptosis of UV-damaged cells, suggesting the potential for incorporation of caffeine in topical formulations intended for use after UV exposure.126
Ferulic acid (4-hydroxy-3-methoxycinnamic acid) is pervasive in the plant world, and considered a potent antioxidant known to provide photoprotection to skin when it is incorporated into cosmetic lotions,127 sunscreens and other skin products.128 Further, it is believed to act synergistically with vitamins C and E, and beta-carotene.129 It is speculated that a topical antioxidant formulation combining vitamins C and E with ferulic acid in a broad-spectrum sunscreen would impart optimal protection to the skin from sun damage.130
Green tea (Cammelia sinensis) polyphenols have been found to be particularly potent at suppressing the carcinogenic activity of UV radiation and to exert broad protection against other UV-mediated responses such as sunburn, immunosuppression and photoaging, and are thus thought to have the potential to protect skin when combined with traditional sunscreens.131 Notably, it is the amount of green tea polyphenols and not the amount of “green tea” in a product that should be considered when evaluating a product. The author recommends products that contain polyphenols in the 90% range, which turns the product brown (which does not indicate that the product has oxidized, as is the case when vitamin C products darken).
Glycyrrhiza glabra extract has been used to treat dermatitis, eczema, pruritus, cysts,132 and skin irritation. In addition, G. glabra has demonstrated antimutagenic, anticarcinogenic, and tumor suppressive capacity against skin cancer in animal models,133,134 and the National Cancer Institute has formally recognized the chemopreventive value of its primary constituent glyccyrrhizin.135 Derived from licorice root (G. glabra), liquiritin has shown efficacy in the treatment of melasma.136 In Europe, licorice extract is widely used as an anti-inflammatory.118
The primary active ingredient isolated and extracted from Glycyrrhiza inflata is licochalcone A, an oxygenated retrochalcone,137,138 which has exhibited anti-parasitic and antibacterial activity,137-140 as well as anti-tumorigenic activity,140,141 and has also been incorporated into a formulation intended to treat rosacea.
This polyphenolic phytoalexin compound, present in the skin and seeds of grapes, berries, peanuts, and other foods,142-144 is considered a potent antioxidant, anti-inflammatory, and anti-proliferative agent.125,145-147 Evidence is sufficiently promising that resveratrol has been deemed suitable for inclusion in various product types (e.g., emollient, patch, sunscreens, and other skin care products) intended to prevent skin cancer and other conditions thought to be generated by the sun.148
Complementary and alternative medicine has become increasingly popular in the US during the past decade and a half. Products derived from botanical sources, often used in traditional or folk medicine, comprise the most popular category of complementary and alternative medical therapies used by Americans. Most such products are available as oral supplements. Several have been incorporated into topical formulations. An increasing number of botanical ingredients are being studied for and used in the medical armamentarium and many have been found to be suitable and beneficial for dermatologic applications, promoting skin health and appearance. Angelica, calendula, curcumin, garlic, ginger, ginkgo biloba, ginseng, silymarin, soy, and tea tree oil have exhibited significant capacity to contribute to skin health. Notably, there are several additional herbal ingredients that confer cutaneous benefits and are incorporated into medical formulations or over-the-counter products.
Not all skin is the same. This is one of the key challenges in the treatment and prevention of dermatologic disease. Skin disease can look very different in Caucasian versus African-American skin. Pigmentation problems common in Asian skin are not seen in northern Europeans. Aging presents differently in men versus women. Adolescents are more likely to develop acne in response to product use than mature individuals. Persons with easy flushing will note stinging and burning with topical products to a much greater degree than the general population. Thus, issues of ethnicity, skin color, age, gender, and skin sensitivity uniquely shape dermatology.
Gender difference issues are some of the most basic when considering cosmetic formulation. Probably the most important difference between male and female skin is skin thickness. Male skin is thicker than female skin, in part due to the presence of terminal hair follicles over much of the body. This difference is most pronounced on the face where women have only vellus hairs while men have fully developed terminal hairs expanding the dermis and subcutaneous space. The presence of male facial hair is partially responsible for the more favorable appearance of mature men over mature women. As UV radiation activates collagenase to destroy dermal collagen, the male beard allows the skin to resist wrinkling, which is not the case in females. Thus, photoaged males do not exhibit the pronounced redundant facial skin seen in photoaged females. This thicker male skin also diffuses UVA radiation more efficiently, preventing the deeper penetration of UVA radiation experienced by female skin. The gender differences in aging are only magnified by the media, which prefers images of younger women and older men.
Differences in skin thickness also impact the frequency of adverse product reactions suffered by the two sexes. Women experience adverse reactions more commonly than men. The thinner skin may allow irritants and allergens to penetrate deeper in female skin, but the increased incidence may also be due to greater product usage. Women overall use more skin care products and cosmetics than men. This increased usage magnifies the chances of contacting an irritant or an allergen. Women are also more likely to undergo procedures that destroy the skin barrier, such as facial peels, microdermabrasion, spa treatments, etc. Furthermore, women are more likely to engage in anti-aging topical products that can create barrier damage, such as topical tretinoin, glycolic acid, lactic acid, etc. This damage to the stratum corneum further increases the chance for magnification of a mild adverse reaction into a more major problem. This artificially created increase in adverse reactions experienced by women has been termed “polypharmacy” by some who wish to impart the concept of overusage of prescription and over-the-counter products by youth-seeking women.
In addition to gender issues, age issues also account for skin diversity. Newborn children produce little sebum and eccrine sweat. Sebum production typically does not begin until the hormonal changes of puberty occur, thus most children have dry skin. This creates a challenge, since children frequently get their skin dirty, which necessitates washing. The child may not produce enough sebum to combat the effect of cleansing that may remove the intercellular lipids resulting in barrier damage. This creates the need for thorough mild cleansers and moisturizers for children. It is for this reason that children are considered to have sensitive skin.
Puberty brings full functioning of the sebaceous, apocrine, and eccrine glands. This may be advantageous to dry skinned children who will no longer suffer from eczema. Many times allergies also become attenuated at this age. But, of course, oil and sweat removal become more of a problem as acne and body odor emerge. The next complection change generally occurs around age 40 as sebum production begins to decline. There is great variability in the age at which sebum production changes. In women, dramatically decreased sebum production occurs at menopause, which usually begins by age 50 and is completed by age 60.
Usually about age 60 there is a transition in both men and women to geriatric skin. Geriatric skin is characterized by skin fragility that results in easy skin tears and bruising due to loss of dermal collagen. Even the rubbing of thick viscous skin creams can cause bruising in elderly skin, medically known as senile purpura. Elderly skin is also unique in that it appears chronically dry, even though noninvasive skin measurements, such as transepidermal water loss, are normal. This may be due to the decreased ability of dead skin scale to slough in a timely manner. The buildup of corneocytes has the appearance of dry skin, even though the viable epidermis is well moisturized. This means that moisturizers selected for geriatric skin should encourage desquamation and provide superior emolliency to smooth the dry appearing corneocytes.
Geriatric skin is uniquely itchy, even though there is little visible evidence of barrier disruption. Severe itching may be reported even though no dermatitis is present. This is a diagnostic enigma for the dermatologist. Skin itching appears to become worse in the postmenopausal female, thus estrogen may play a role. However, the exact cause of the itching is not always apparent. It may be due to depression, poor dermal support of the nerve endings, abnormal intercellular lipids, etc. Thus, itch reduction is a skin care need in the elderly.
We shall now turn our discussion to skin color. Skin color accounts for a large part of the diversity seen in dermatology. All colors of skin possess melanin, but differences arise from melanin packaging creating light and dark skin and the accompanying sunburn characteristics. Very light skin that does not tan well typically does not respond to injury with pigmentation problems. There may be some transient hypopigmentation with eczematous conditions, however a burn injury usually results in postinflammatory hyperpigmentation. This is in contrast to persons with darker skin, to include Asian, Mediterranean, African-American, and Hispanic skin, who experience frequent postinflammatory hyperpigmentation, which is a larger cosmetic concern than wrinkling in these ethnic groups.
Skin color also confers photoprotection. Darker skin can sunburn and tan just like fair skin, but deepening of the skin color is generally considered undesirable. This is not the case in fair complected individuals who try to achieve a tan by natural sun exposure, the use of artificial UVA radiation in a tanning booth, or dyeing of the skin with self-tanning products containing dihydroxyacetone. Melanin is basically an unstable radical that can absorb an electron from highly energetic unstable oxygen species, preventing the activation of collagenase and the resulting dermal damage. This is why darker complected persons typically do not demonstrate photoaging to the same degree as their lighter age matched counterparts.
In addition to the different skin color responses to injury and photoaging, another important reaction pattern, known as follicular predilection, is unique to darker skin. Follicular predilection refers to the presence of disease around the follicular ostia. Whether this reaction pattern is due to the increased melanin or the unique hair architecture hair is unknown, but this type of eczema is considerably more difficult to treat. Thus, dermatoses and problems associated with skin care products or cosmetics may appear differently in heavily pigmented skin, sometimes confusing the proper diagnosis.
Probably the biggest formulation challenge for the cosmetic chemist and the biggest treatment challenge for the dermatologist is sensitive skin. Sensitive skin can present with visible outward changes, easily recognized by the dermatologist, or invisible signs with marked symptoms presenting a treatment challenge.
Visible sensitive skin is the easiest condition to diagnose, since the outward manifestations of erythema, desquamation, lichenification, and inflammation identify the presence of a severe barrier defect. Patients with barrier defects possess the signs and symptoms of sensitive skin until complete healing occurs. The three most common dermatologic causes of barrier defects are eczema, atopic dermatitis, and rosacea. These conditions are characterized by barrier disruption, immune hyper-reactivity, and a heightened neurosensory response.
Rosacea deserves special consideration, since this condition presents challenges both in the prescription and the OTC realm. Patients with rosacea experience stinging and burning more frequently than the general population to minor irritants. This is confirmed by the fact that 62.5% of randomly selected rosacea patients demonstrated a positive lactic acid sting test.(1) Whether this sensitive skin is due to nerve alterations from chronic photodamage, vasomotor instability, altered systemic effects to ingested histamine, or central facial lymphedema is unclear.
Eczema, atopic dermatitis, and rosacea are in some ways the easiest forms of sensitive skin to treat. The skin disease is easily seen and treatment success can be monitored visibly. If the skin looks more normal, generally the symptoms of itching, stinging, burning, and pain will also be improved. Unfortunately, there are dermatologically challenging patients who present with sensitive skin and no clinical findings. These patients typically present with a bag full of skin care products they claim cannot be used because they cause facial acne, rashes, and/or discomfort. This has led to a new market segment containing products designed for sensitive skin. Exactly what is unique to sensitive skin products is unclear. In many ways, it is simply a marketing statement, however some manufacturers will elect to test their formulations in persons with eczema, atopic dermatitis, and rosacea as part of a sensitive skin panel to substantiate the claim.
Sensitive skin formulations may also bear the label “hypoallergenic.” Exactly what hypoallergenic means is unclear. In the strictest sense, the word hypoallergenic is used to indicate reduced allergy. Many products that are labeled hypoallergenic are also labeled as appropriate for sensitive skin, but the claims are somewhat different. All sensitive skin products should be hypoallergenic, but all hypoallergenic products are not necessarily appropriate for sensitive skin. In my mind, hypoallergenic simply means that common allergens have been removed from the formulation, but irritants may still be present.(2)
Formulating products with reduced allergy is sometimes difficult. It is obvious that poison ivy, a common allergen, should never be included as an ingredient, but other guidelines are sometimes difficult to develop. It is probably for this reason that hypoallergenic has never been defined by any regulatory body. Hypoallergenic products are probably best formulated by using the fewest, purest ingredients possible and staying away from unusual botanical extracts. A poor approach would be to put anti-inflammatory substances, such as bisabolol or allantoin, in the formulation to minimize any allergic reaction. A quick review of the contact dermatitis literature shows that the most commonly cited cases of skin care product induced problems arise when contaminated raw materials are used, such as nickel contaminated eye shadow pigments or oxidized vitamin E, or when product preservatives break down. The best guarantee of formulating a hypoallergenic product is to use time tested ingredients in a stable formulation.
Skin diversity also creates different predilections to the formation of comedos and acne. Noncomedogenic and nonacnegenic are two claims used to designate the safety of OTC products for individuals with skin exhibiting this pathology. Comedogenicity was a much greater problem when petrolatum was contaminated with tar, a known comedogen. Presently, comedogenicity is not a great problem, except in the ethnic hair care market where comedogenic vegetable oils, such as olive oil, are used in pomades to moisturize the hair.
Testing must be done to substantiate the noncomedogenic nature of products. In the past, comedogenicity was assessed in the rabbit ear assay by applying the final formulation inside a rabbit ear and then visually assessing the presence or absence of comedones. This test was not felt to have much human validity and animal testing has fallen out favor, thus the rabbit ear assay has given way to testing on human volunteers. Typically, the final formulation for testing is applied to the upper back in persons capable of forming comedones on the upper back daily for 14 days. A positive control, in the form of tar is applied, and a negative control, in the form of pure petroleum jelly, is also used. The comedones are extracted from the upper back with cyanoacrylate glue placed on a microscope slide. Any increase in comedone formation following the 14-day exposure to the final cosmetic formulation is considered comedogenic.
The nonacnegenic claim is much different. It implies that the finished product does not produce true acne. It takes much longer for acne to develop from product use, typically about 4 weeks. There is no standard test done for acnegenicity, except for use testing. Volunteers use the product as intended for one month and are examined for the presence of papules and pustules. Yet, there are a number of individuals who will develop tiny perifollicular papules and pustules within 48 hours of wearing a skin care product or cosmetic. Is this acne? The answer is no. True acne cannot develop in 48 hours. In my opinion, this is perifollicular irritant contact dermatitis. It looks much like acne, but the presence of lesions at the follicular ostia and the rapid onset lead to the diagnosis of perifollicular contact dermatitis. This problem is best avoided by minimizing the presence of irritants in the formulation.
Swimming is the most challenging sport for the skin. Skin has a protective layer of fats, known as lipids that make the skin semi-waterproof. This lipid layer is much better developed in mammals that live in the water, such as beavers. Since your swimmer is not a beaver, prolonged water contact can remove these lipids damaging the protective skin barrier. Once damaged, the skin barrier will begin to renew itself automatically, but flaking, itching, stinging, and burning may be part of the process. The first substance produced by the body as part of the repair process is ceramide, an ingredient found in some therapeutic skin moisturizers. You can identify this healing ingredient by looking at the product ingredients.
In addition to water damage, swimmers are also exposed to chlorine and other poor chemicals. These chemicals are vital to preventing skin infections, such as impetigo from bacteria, warts from viruses, and athlete’s foot from fungus. However, chlorine can also accelerate the removal of the fats from the skin damaging the skin barrier. It is critical to remove chlorine from the skin by proper cleansing.
Swimmers should rinse the skin immediately after swimming and, if possible, bathe with a gentle cleanser. Actually, the water and chlorine in the pool are pretty good at removing much of the sebum, sweat, and environmental dirt from the skin, making excessive scrubbing and cleansing unnecessary. Rinsing and gentle bathing is necessary to remove the chlorine smell from the skin and prevent excessive chlorine irritation. If a strong chlorine smell is left on the skin after swimming, it may be worthwhile to check the pool chemicals as a well-balanced pool has minimal chlorine smell.
The best way to keep your swimmer’s skin healthy is to prevent skin barrier damage in the first place. Consider moisturizing morning and evening with a ceramide-containing cream liberally applied to all body areas, but especially the arms and legs where oil production is minimal. Creams provide more moisturizing than lotions, but lotions may be preferred by oily complected teenagers. Choose the product that meets the needs of your swimmer.
Red, itchy skin may be a sign of excessively dry skin, a condition known as eczema. Very mild eczema may be treated with over-the-counter 1% hydrocortisone cream twice daily, but if this remedy does not improve the skin in 2-3 days you may want to seek the professional guidance of a dermatologist.
Women are not petite men. Men are not muscular women. Women are not longhaired men. Men are not bearded women. The real difference between women and men begins with the skin, but manifests in profound physical, emotional, and mental attributes. Several years ago, a popular book pronounced that men were from Mars and women were from Venus. This is the subject of intense ongoing debate. The magnitude of differences between men and women cannot be elucidated in this short article, but some insight into the dermatologic uniqueness of men and women can be highlighted. Differences in skin structure, biochemistry, and functionality are worthwhile exploring as they may explain the gender aspects of dermatologic disease.
While obvious differences exist between men and women concerning hair growth patterns, the other subtle aspects of skin structure uniqueness may not be so apparent. For example, male skin is more deeply pigmented than female skin, perhaps accounting for the saying that women are the “fairer” of the species. Male skin is also thicker and thus contains more collagen. This may explain why women appear to age more quickly than men, as both genders experience the same rate of collagen loss, but women begin with a lower baseline and loose proportionately more collagen. Women, on the other hand, possess more subcutaneous fat, which predisposes to cellulite and creates less muscle definition. Gender specific fat also distributes in different body areas, with men depositing truncal fat while women deposit more gluteal and femoral fat.
Men age slower than women, not only due to increased skin thickness, but also due to the presence of facial hair. As the collagen is degraded with intrinsic and extrinsic aging, the terminal hair bulbs on the face take up more of the space. This prevents the fine cigarette paper wrinkling on the cheeks primarily found in women. It will be interesting to see how male skin ages after permanent laser hair removal on the face, which is becoming more popular in certain geographic areas.
Structural skin differences can be visibly appreciated, but skin biochemical differences are equally important. Males secrete more sebum than females throughout life. While female sebum production dramatically decreases after menopause, male sebum secretion continues. This reduction is sebum is also accompanied by a reduction in stratum corneum lipids in females, which may be attributed to a reduction in estrogen with advancing age. This sebum reduction may explain why mature males have a higher incidence of seborrheic dermatitis than mature females.
There are also differences in the ability of female vs. male fibroblasts to proliferate. Female fibroblasts proliferate at a 16% higher rate than male fibroblasts at age 30. This may explain why females tend to heal better than males, especially after facial surgery. Another explanation for superior healing may also be the reduced thickness of female facial skin.
While differences exist in skin structure between males and females, there are also differences in the substances that are present on the skin surface. Males tend to sweat more than females, creating an environment more conducive to bacteria growth resulting in odor production. Male sweat also remains on the skin longer. In addition, males possess more body hair, which increases the body surface area for bacterial colonization. This may the increased popularity of antibacterial soaps among men. The presence of sweat may also contribute to differing skin pH measurements between men and women. Women have a higher more alkaline pH, while men have a relatively lower pH, but the pH of the axilla is identical in both sexes.
Finally, women have a higher transcutaneous oxygen level than men. The exact significance of this is not known, but may be explained by the thinner epidermis.
In addition to skin biochemical differences, there are also differences in skin functionality. These functional differences can impact how skin care products perform on the skin and may dictate product formulation specifics. It is interesting to note that transepidermal water loss is lower in females than males, even though women feel that their skin is drier when polled. Women also generally feel that their skin sags more than men, but skin elasticity is identical between the sexes. The increased impression of sagging may be due to thinning collagen rather than decreased skin elasticity.
Female skin is more functionally responsive than male skin. This is manifested by the lower temperature at which heat induces vasodilatation. It also presents as an increase in irritant contact dermatitis and increased sympathetic tone. This may explain why females exhibit increased redness and irritation to skin care products, sometimes referred to as “tender” skin, over males, who are characterized as having “tough” skin.
It is also interesting to note that females possess cooler skin than males, especially at the fingertips. Could this be why women tend to have cold hands as compared to their male counterparts? Could this also explain why women complain of being cold more than men? While many of these observations have been linked to personal perception, it may indeed be true that gender unique skin physiology is more important than previously thought.
The differences between male and female skin structure, biochemistry, and functionality are interesting from a pure scientific standpoint. However, these facts are more than just trivia to impress colleagues at the country club Christmas party. These gender differences are used to develop skin care products that meet the needs of the intended consumer. For example, odor control is much more challenging in males than females due to body hair and the increase production of both sweat and sebum, providing excellent growth media for bacteria. The fact that facial stinging is much more prevalent among females points to the need to test female facial skin care products and cosmetics for sensitive skin. Less collagen and thinner facial skin in women creates a larger female anti-aging skin care market. Finally, increased body fat makes cellulite treatments aimed at women a market segment, while male cellulite products are nonexistent.
Marketing experts at all skin care companies spend a great deal of time examining gender differences and understanding the intended end user of their products. Male products are not the same as female products except for packaging in a blue box. Female products are not the same as male products except for the floral fragrance. Understanding gender differences and formulating appropriately are important for the cosmetic chemist.
This article has examined the key differences between male and female skin structure, biochemistry, and function. I will leave it up to the reader to determine if men are from Mars and women are from Venus.
It is amazing to think that aging begins at birth with the very first breathe of oxygen. Oxygen is necessary for human life and human aging. We are young growing old with each inhalation creating oxygen radicals that damage our carbon based structure. How exactly does this happen? This article will examine our current understanding of oxidative aging and how it affects everyone and everything on the planet.
Oxygen is a relatively new element to our plant with its origin about 2 billion years ago when water-splitting microorganisms first released oxygen to create our atmosphere. The development of plants engaged in photosynthesis further increased the atmospheric oxygen some of which ended up as UV protective ozone. The oxygen molecule possesses two unpaired electrons, which makes it a diradical. When a molecule accepts an electron, it undergoes a reduction reaction, while when it loses an electron it undergoes an oxidation reaction. It is the univalent reduction of oxygen, or the addition of one electron at a time, that produces reactive oxygen species. These reactions are diagramed below:
Oxygen + one electron = Superoxide (O2-)
Superoxide + one more electron = Hydrogen peroxide (H2O2)
Hydrogen peroxide + one more electron = Hydroxyl radical (·OH)
Hydroxyl radical + one more electron + hydrogen = Water (H2O)
Only the superoxide and hydroxyl radical are considered free radicals. While hydrogen peroxide is a reactive oxygen species, it is not a free radical, and water, of course, is completely stable. There is a fourth type of reactive oxygen species known as singlet oxygen. These are the basic interactions of hydrogen and oxygen involved in human respiration.
Oxygen can react with other elements one electron at a time, besides hydrogen, including transition metals. The most physiologically relevant transition metal is iron, found in the red blood cells bound to hemoglobin for carrying oxygen. The reaction of oxygen with iron in the environment is known as rust. Iron is able to accept and transfer oxygen molecules. Gold, for example, does not rust because it cannot interact with oxygen.
Superoxide is created by adding one electron to molecular oxygen creating a highly reactive molecule with one or more unpaired electrons. Superoxide forms when UV radiation strikes oxygen and can be created by certain enzymatic reactions as part of metabolism. Superoxide can react with itself irreversibly to produce hydrogen peroxide in the reaction outlined below:
O2- + O2- + 4H ==> H2O2
The hydrogen peroxide can be destroyed by peroxidases, which convert the hydrogen peroxide to oxygen and water. While hydrogen peroxide is not a powerful oxidant, it is damaging to body tissues because it can diffuse rapidly across cell and nuclear membranes. Hydrogen peroxide can also be converted to the hydroxyl radical in the presence of iron, which can react with and damage DNA as illustrated below:
H2O2 + FeII ===> ·OH + -OH + FeIII
This is why exogenous hydrogen peroxide is used as a skin surface disinfectant and is manufactured by the body as part of the innate immune system to topically kill foreign organisms. Hydrogen peroxide is also produced by superoxide dismutase and crosslinks or denatures proteins.
The hydroxyl radical produces most of the cellular oxidative damage to nuclear DNA. Hydroxyl radicals are able to interact with the purine and pyrimidine bases damaging the DNA code, but repair mechanisms are in place to remove the damaged bases.
When oxygen is irradiated with UV, it will absorb the energy and change its molecular configuration. Singlet oxygen is created when one of the unpaired electrons is elevated to a higher energy level, and most importantly, its spin number is inverted. This allows the single oxygen to damage proteins and the double bonds in fatty tissue and cell walls. This damage is known as oxidative stress.
Oxidative stress occurs when body structures are damaged over time with repeated insults, which cumulatively are labeled as aging. For example, superoxide attacks unsaturated fatty acids in the cell membrane damaging its integrity. When unsaturated fatty acids are oxidatively damaged in foods, the food is said to be rancid. Aging is basically rancidity of the human body. When the fatty acids are damaged in the body an amorphous yellow material known as lipofuscin is produced. Lipofuscin can accumulate in the skin and accounts for the dusky yellow hue characteristic in the facial skin of heavy tobacco smokers. This lipid peroxidation requires one or more double bonds to occur. It commonly occurs in the essential fatty acids of the body, such as linolenic acid, because it possesses three double bonds. The reaction is outlined below:
(1) PUFA + Superoxide ====> Lipid free radical
(2) LFR + Oxygen ====> Peroxyl lipid radical
(3) Peroxy lipid radical + PUFA ====> Lipid hydroperoxide + LFR
The reaction of superoxide with a polyunsaturated fatty acid (PUFA) produces a lipid radical that reacts in turn with molecular oxygen to form a peroxy lipid. The peroxy lipid in turn reacts with an adjacent PUFA to steal a hydrogen atom and form a lipid hydroperoxide. The lipid hydroperoxide is then decomposed either by catalase or another enzyme into more reactive components that can cross-link or denature proteins. One of these reactive byproducts is malonyldialdehyde, abbreviated MDA. MDA is a marker of lipid peroxidation and systemic levels can be used to determine the amount of oxidative stress the body has endured. Vitamin E is an important antioxidant to prevent the formation of MDA.
The body must protect itself from oxidative stress for survival. As a matter of fact, persons who age more slowly may have better oxidative stress protection than those who age rapidly. The endogenous mechanisms for oxidative stress protection are summarized in Table 1. Of these, intracellular vitamin E is important in preventing the hydroxyl radical reaction by stopping the chain reaction of lipid peroxidation. Vitamin C functions as a secondary antioxidant by regenerating active vitamin E. This represents an oxidation-reduction where vitamin E loses a hydrogen molecule to the hydroxyl radical and is thereby oxidized. Vitamin C reduces the vitamin E back to an active form by donating a hydrogen molecule. The reaction is summarized below:
Vitamin E-OH + ·OH ===> Vitamin E = O + H2O
Vitamin E = O + Vitamin C ===> Vitamin E-OH + Oxidized vitamin C
This reaction can occur with vitamin C, uric acid, and glutathione. Without this type of oxidative protection, the body would age rapidly and die. Aging is basically oxidation of the human organism. It may be that the secret to youth is in developing a human preservative!
Treating sensitive skin can indeed present a challenge to the dermatologist, since formulations that are typically not problematic for the general population cause intense stinging, burning, and redness in individuals with sensitive skin. Patients with sensitive skin can either present with skin that appears normal to the eye or overt skin disease. Those with overt skin disease are sometimes easier to evaluate, since visual inspection can provide an idea of how to approach the problem. This is the perplexing part of treating sensitive skin.
Visible sensitive facial skin is the easiest condition to diagnose, since the outward manifestations of erythema, desquamation, lichenification, and inflammation identify the presence of a severe barrier defect. Any patient with a barrier defect will possess the signs and symptoms of sensitive skin until complete healing occurs. The three most common causes of barrier defect induced facial sensitive skin are eczema, atopic dermatitis, and rosacea. These three diseases nicely illustrate the three components of sensitive skin, which include barrier disruption, immune hyper-reactivity, and heightened neurosensory response.
Eczema is characterized by barrier disruption, which is the most common cause of facial sensitive skin. The barrier can be disrupted chemically through the use of cleansers and cosmetics that remove intercellular lipids or physically through the use of abrasive substances that induce stratum corneum exfoliation. In some cases, the barrier may be defective either due to insufficient sebum production, inadequate intercellular lipids, abnormal keratinocyte organization, etc. The end result is the induction of the inflammatory cascade accompanied by erythema, desquamation, itching, stinging, burning, and possibly pain. The immediate goal of treatment is to stop the inflammation through the use of topical, oral, or injectable corticosteroids, depending on the severity of the eczema. Newer topical options for the treatment of eczema induced sensitive facial skin include the calcineurin inhibitors, pimecolimus and tracrolimus.
However, the resolution of the inflammation is not sufficient for the treatment of eczema. Proper skin care must also be instituted to minimize the return of the conditions that led to the onset of eczema. This includes the selection of maintenance skin care products, such as cleansers and moisturizers. Thus, the care of sensitive skin involves not only the treatment of the acute skin disease, but also the prevention of recurrence through proper skin care maintenance.
Sensitive facial skin due to eczema is predicated only on physical barrier disruption, while the sensitive facial skin associated with atopic dermatitis is predicated both on a barrier defect and an immune hyper-reactivity, as manifested by the association of asthma and hay fever. Patients with atopic dermatitis not only have sensitive skin on the exterior of the body, but also sensitive mucosa lining the eyes, nose, and lungs. Thus, the treatment of sensitive facial skin in the atopic population involves topical and systemic considerations. There is also a prominent link between the worsening of hay fever and the onset of skin symptoms, requiring broader treatment considerations.
All of the treatments previously described for eczema also apply to atopic dermatitis, but additional therapy is required to minimize the immune hyper-reactivity. While this may take the form of oral or injectable corticosteroids, antihistamines (hydroxyzine, cetirizine hydrochloride, diphenhydramine, fexofenadine hydrochloride, etc.) are typically added to decrease cutaneous and ocular itching. Antihistamines also improve the symptoms of hay fever and may prevent a flare should the patient be exposed to pollens or other inhaled allergens. The avoidance of sensitive skin in the atopic patient is largely predicated on avoidance of inciting substances. This means creating an allergy free environment by removing old carpet, nonwashable drapes, items likely to collect dust, feather pillows and bedding, stuffed animal toys, heavy pollinating trees and plants, live pets, etc. The prevention of the release of histamine is the key to controlling the sensitive facial skin of atopic dermatitis.
Rosacea is an example of the third component of sensitive facial skin, which is heightened neurosensory response. This means that patients with rosacea experience stinging and burning more frequently than the general population to minor irritants.(1) Whether this sensitive facial skin is due to nerve alterations from chronic photodamage, vasomotor instability, altered systemic effects to ingested histamine, or central facial lymphedema is unclear.
The treatments for rosacea-induced sensitive facial skin are much different than those for eczema or atopic dermatitis. Anti-inflammatories in the form of oral and topical antibiotics form the therapeutic armamentarium. Antibiotics of the tetracycline family are most commonly used orally, while azelaic acid, metronidazole, sulfur, and sodium sulfacetamide are the most popular topical agents. However, the effect of the anti-inflammatory antibiotic can be enhanced through the use of complementary skin care products that enhance barrier function.
Eczema, atopic dermatitis, and rosacea are in some ways the easiest forms of sensitive skin to treat. The skin disease is easily seen and treatment success can be monitored visibly. If the skin looks more normal, generally the symptoms of itching, stinging, burning, and pain will also be improved. Unfortunately, there are some patients who present with sensitive facial skin and no clinical findings. These patients typically present with a bag full of skin care products they claim cannot be used because they cause facial acne, rashes, and/or discomfort. This situation presents a challenge for the physician, since it is unclear how to proceed.
Several treatment ideas are worth considering. The patient may have subclinical barrier disruption. For this reason, treatment with an appropriate strength topical corticosteroid for 2 weeks may be advisable. If symptoms improve, then the answer is clear. The patient may have subclinical eczematous disease. If the symptoms do not improve, it is then worthwhile to examine the next most common cause of invisible sensitive skin, which is contact dermatitis. This is accomplished by considering the ideas presented in Table 1. However, it may be worthwhile to consider some of the newer cosmeceutical moisturizer ingredients to aid in minimizing the inflammation. This is the next topic of discussion.
This article began with an overview of the prescription treatments for the three components of sensitive skin to include barrier disruption, immune hyper-reactivity, and heightened neurosensory responsiveness. Each of these components activates the inflammatory cascade, which is the final common pathway for all skin diseases, including sensitive skin. In addition to prescription therapies, a variety of cosmeceutical botanicals have been studied that may be helpful in the maintenance phase of sensitive skin treatment. These botanical anti-inflammatories include ginkgo biloba, green tea, aloe vera, and allantion. They are most relevant to the sensitive facial skin patient in the form of topical moisturizers, which may help reduce the symptoms.
Ginkgo biloba is a plant with numerous purported benefits that is a common part of homeopathic medicine in the Orient. The plant leaves contain unique polyphenols such as terpenoids (ginkgolides, bilobalides), flavinoids, and flavonol glycosides that have anti-inflammatory effects. These anti-inflammatory effects have been linked to antiradical and antilipoperoxidant effects in experimental fibroblast models. Another aspect of ginkgo in relation to sensitive skin is its ability to modify skin microcirculation. Vascular alterations induced in the skin include a blood flow decrease at the capillary level and a vasomotor change in the arterioles of the subpapillary skin plexus. These changes may lead to decreased skin redness, sometimes a concern of patients with sensitive skin.
Green tea, also known as Camellia sinensis, is another anti-inflammatory botanical containing polyphenols, such as epicatechin, epicatechin-3-gallate, epigllocatechin, and eigallocatechin-3-gallate. The term "green tea" refers to the manufacture of the botanical extract from fresh leaves of the tea plant by steaming and drying them at elevated temperatures, being careful to avoid oxidation and polymerization of the polyphenolic components. A study by Katiyar, et al, demonstrated the anti-inflammatory effects of topical green tea application on C3H mice.(3) A topically applied green tea extract containing GTP ((-)-epigallocatechin-3-gallate) was found to reduce UVB-induced inflammation as measured by double skin-fold swelling.(4) Green tea containing moisturizers may be valuable in the sensitive skin patient.
The most widely used cutaneous botanical anti-inflammatory is aloe vera. The mucilage is released from the plant leaves as a colorless gel and contains 99.5% water and a complex mixture of mucopolysaccharides, amino acids, hydroxy quinone glycosides, and minerals. Compounds isolated from aloe vera juice include aloin, aloe emodin, aletinic acid, choline, and choline salicylate. The reported cutaneous effects of aloe vera include increased blood flow, reduced inflammation, decreased skin bacterial colonization, and enhanced wound healing. The anti-inflammatory effects of aloe vera may result from its ability to inhibit cyclooxygenase as part of the arachidonic acid pathway through the choline salicylate component of the juice. However, the aloe vera final concentration in any moisturizer must be at least 10% to achieve a cosmeceutical effect.
Allantoin is the commonly added anti-inflammatory ingredient to moisturizers labeled as designed for sensitive skin. It naturally found in the comfrey root, but synthesized in large quantity by the alkaline oxidation of uric acid in a cold environment. It is a white crystalline powder that is readily soluble in hot water, making it easy to formulate in cream and lotion moisturizers designed for sensitive skin.
In many cases, it is impossible to determine the exact cause of the sensitive skin. No obvious skin disease is present, yet the patient notes intense stinging and burning whenever skin care products or cosmetics are applied to the skin. Frequently patch testing reveals no obvious source of irritant or allergic contact dermatitis. This then leaves the physician to use empiric methods to make product recommendations to the patient. Products must be carefully selected based on the use of ingredients that are least likely to damage the skin barrier, elicit a noxious sensory response, or alter the skin structure. Products with botanical anti-inflammatories may be helpful, but most patients want specific suggestions on how to select skin care products and cosmetics. This section discusses the approach I use in my practice for product selection in the sensitive skin patient who has not responded any of the previously outlined treatment modalities.
Even patients with sensitive skin require basic hygiene. The face and body must be cleansed. There is no doubt that the synthetic detergent cleansers, also known as syndets, provide the best skin cleansing while minimizing barrier damage. Bars based on sodium cocyl isethionate appear to perform the best. There are some patients, however, who only require the use of a facial syndet cleanser occasionally, since sebum production and physical activity are minimal. For these patients, a lipid-free cleanser is preferable because it can be used without water and wiped away. These products may contain water, glycerin, cetyl alcohol, stearyl alcohol, sodium laurel sulfate, and occasionally propylene glycol. They leave behind a thin moisturizing film and can be used effectively in persons with excessively dry, sensitive, or dermatitic skin. They do not have strong antibacterial properties, however, and may not remove odor from the armpit or groin. Lipid-free cleansers are best used where minimal cleansing is desired.
After completing cleansing, the sensitive skin patient requires moisturization. The moisturizer should create an optimal environment for barrier repair, while not inducing any type of skin reaction. For example, the product should not contain any mild irritants that may present as an acneiform eruption in the sensitive skin patient due to the presence of follicular irritant contact dermatitis. The best moisturizers are simple oil-in-water emulsions. The most common oil used is white petrolatum, but dimethicone and cylcomethicone are also acceptable oils in the sensitive skin population for decreasing the greasiness of a simple petrolatum and water formulation. As mentioned previously, the fewer ingredients the better.
Sensitive skin females also require recommendations on proper cosmetic selection. This can be a challenge for the physician, since cosmetic formulations change rapidly as dictated by the needs of fashion. The best method for evaluating problematic facial cosmetics is the provocative use test, performed by applying a 2 cm area of product lateral to the eye for 5 consecutive nights. This allows isolation of the cosmetic products one at a time on the most sensitive part of the face, which has the highest yield of uncovering the problem.
The treatment of sensitive skin is a medical challenge. Any treatment must address the barrier disruption, immune hyper-reactivity, and heightened sensory responsiveness that characterize sensitive skin. If the sensitive skin is due to a visible dermatosis, the treatment can be streamlined, but if the sensitive skin is invisible, a long treatment algorithm must be followed to further elucidate valuable diagnostic information. Finally, basic skin care and cosmetic recommendations can be made to the sensitive skin consumer to minimize the chances of encountering a problem.
Cellulite is uneven bumpy skin. It has been described as an “orange peel” or “cottage cheese” skin appearance. This appearance is due to projections of fat into the layer of skin, known as the dermis.
Cellulite can be located anywhere are the body than contains fat. Certain areas are more likely than others, however. Cellulite is most commonly seen on the upper outer thighs, the posterior thighs, and buttocks, but can also be seen on the breasts and upper arms. It seems to be found in areas where excess fat is deposited, although obesity is not necessary for the presence of cellulite. The pattern of fat deposition that leads to cellulite may be genetically determined.
The appearance of cellulite is not observed until after puberty in females. It is uncommonly seen in men, perhaps because the presence of cellulite is due to female hormones. Cellulite may be considered a normal body change associated with puberty and cannot be considered a disease, since it is seen in an estimated that 85% of females.
There are some interesting racial differences in the presence of cellulite, however. Cellulite is more commonly seen in Caucasian females than Oriental females. It is true that it is easier to visualize skin texture irregularities in fair skin, yet Oriental females seem to demonstrate less cellulite. Many theories have been advanced to try and explain this difference. Some feel that the reduced cow’s milk consumption in the Orient is the reason, since much of the milk consumed in the United States contains estrogens that enter the milk from the food fed to the cows. Anther possible explanation is reduced estrogen production in Oriental females who consume large amounts of fermented soy in the form of tofu or soy nuts. Fermented soy is high in phytoestrogens, which may decrease estrogen production.
There are a variety of products on the market for reducing cellulite. I am not sure that any of them work tremendously, but it is worthwhile looking to see what they contain.
This product is based on caffeine, which is a beta-adrenergic stimulator believed to turn on the elimination of fat, known as lipolysis. The caffeine-induced lipolysis is thought to reduce the fat and improve cellulite while promoting slimming. In addition, it contains a variety of botanical anti-inflammatories including Ginkgo biloba, mallow extract (Malva sylvestris), and hare’s ear (Bupleurum falcatum). Since inflammation is a known component of cellulite, these anti-inflammatories are also felt to assist.
This product is also based on caffeine, but includes retinol. There were some dermatologists about a decade ago who advocated the use of tretinoin, also known as Retin-A, in treating cellulite. For this reason, many cosmetic formulators use the OTC retinoid retinol in cellulite preparations.
This formulation is based on a seaweed extract (Fucus vesiculosis) that has anticoagulant properties. It is also thought to enhance fibroblast expression of integrins, which increases collagen thickness preventing the herniation of fat into the dermis from the subcutaneous compartment. In addition, this formulation has Centella asiatica that is used orally in some slimming nutritional supplements to induce lipolysis.
This formulation combines all of the ingredients previously discussed to include caffeine, seaweed, and retinol. The idea is to put in as many ingredients as possible to benefit the appearance of cellulite subscribing to the theory that more is better. The seaweed extract used is red seaweed hydrolyzate that contains k-carrageenan that can react with spermine and spermidine. These polyamines are thought to trigger the accumulation of fat. If they are inhibited perhaps the accumulation of fat is also inhibited decreasing cellulite.
Shaving is a daily activity practiced by both men and women. A few helpful hints can turn a shaving disaster into a shaving success.
Razor selection is perhaps one of the most important considerations for achieving an excellent hair removal result. Without good tools, a good result cannot be obtained. Many people complain that shaving causes pain, discomfort, and razor burn. When asked what type of razor they select, many will state that they buy a big bag of disposable razors for under $5. In the area of razor purchase, you get what you pay for. Cheap razors do not provide the best hair removal.
First, the disposable razors are made out of a thin plastic shell and are not weighted. A good razor with replaceable cartridge blades will be weighted in the handle to insure that the blades strike the skin at the proper angle. When the razor is held in the hand, the head angles the blade to meet the skin for optimal hair removal while minimizing skin removal. Second, disposable razors generally do not have high quality laser cut, spring mounted blades. These two advances in razor design lead to less skin irritation. In summary, if the razor blade is not well cut and not well mounted in the handle, a good shave cannot be obtained.
Selecting a well-designed razor and a state-of-the-art blade is also important. The first razors to enter the market were single edged. The double-edged razor replaced the single blade razor when it was recognized that the first blade lifts the hair from the skin surface for cutting by the second blade. This lifting of the hair increases the chances for a close shave while minimizing the unnecessary removal of skin, a condition commonly known as razor burn.
The next development in razor design was the addition of glide strip. This strip placed on the leading edge of the blade was intended to reduce friction when the razor was dragged across the skin leading to fewer problems when shaving over curved surfaces. The strip was later loaded with skin conditioning agents, such as aloe, to provide additional skin benefits. The loaded glide strip was problematic in some of the early razor designs as the moisturizer became stringy and clogged the blades. This problem has now been overcome by the use of a thinner more flexible glide strip.
The most significant development in razor design has been the development of five multibladed razors. The hair is lifted and successively cut by each of the blades to produce a very close shave without using undue razor pressure on the skin. Blade pressure on the skin leads to razor burn. The multibladed razor produces a close shave without the requirement of pressure causing less razor burn, less skin irritation, and fewer skin cuts. Further shaving pressure reduction can be created by vibrating the razor and manually dragging it over the skin surface. This is the rationale behind the new battery operated razors.
The most expensive razor blades also have laser cut blades with spring mounts, in addition to multiple blades. The laser cut blades have a more accurate edge with fewer defects providing for less razor burn and a closer shave. The springs help to allow the blades to rotate over the skin surface reducing cuts and providing a close shave over curved surfaces, such as the chin or the knees. While these blades carry a higher cost, the extra expense is well justified. There is no substitute for a blade that is designed for optimal performance.
An expensive blade requires excellent care to deliver a superior shave over the blade lifetime. It is important to use good blade care to prevent blade damage that compromises the shave quality. Razor blades should not be stored in the wet environment of the shower. They should be allowed to dry between shaves and kept in a dry location, such as the counter top or the drawer. Prior to drying, the blades should be thoroughly rinsed of hair and skin debris to prevent the material from sticking to the blade and compromising the sharp edge.
It is also important not to drop the blade or bang it into other objects. Dropping the razor on the blade creates a dull spot on the edge. There is a saying in razor blade technology that “the patient always shaves with the dullest portion of the blade.” This means that razor burn results from the damaged blade areas, not the sharp blade areas. If the blade is only 5% damaged and 95% undamaged, razor burn will still occur even though the majority of the blade is still in optimal condition. Most razor blades are designed to be used for 5-7 shaves, meaning that the blade should be replaced at least on a weekly basis.
A good well maintained blade is part of the equation for a superior shave, but the shaving cream is equally important. The shaving cream creates the interface between the blade and the skin. A good interface sets the stage for a good shave and a poor interface sets the stage for a poor shave. Many feel that a shaving cream is extraneous and use nothing, or other items handy in the bath such as bar soap, shampoo, or hair conditioner. It is important to remember that all personal care products are carefully designed for their intended purpose and are not well suited for any other use. Bar soaps, shampoo, and hair conditioner leave a film on the blade hastening blade dulling and do not optimally alleviate friction between the blade and the skin. Shaving cream is specially designed for this purpose.
There are many shaving products on the market. Some of them are old fashioned soaps applied with a brush, some are dispensed and warm when rubbed on the face, others are foams squirted from a can, and the best are gels dispensed from and aerosol can that foam when rubbed on the face. The later are known as post-foaming shave gels. The post-foaming shave gel is the best choice for persons with shaving challenges because they entrain water better than any other type of shave product. Entraining water is the event that occurs when the hair shaft becomes hydrated. Hydration is the first step in preparing the hair for cutting because the keratin softens and can be cut with less force. A dry hair likened to a similar diameter copper wire while a wet hair is likened to an aluminum wire. Aluminum is much easier to cut than copper. These metals are used to model the physical dynamics of shaving.
The proper way to prepare the skin for shaving is by washing the face and then thoroughly wetting the face with lukewarm water. This wetting step places a thin layer of water over the hair and skin. Next, the shaving gel should be dispensed from the can and placed in the palm. The palms should be rubbed together to generate a rich foam which is generously applied to the premoistened face. The shaving gel should remain on the face for 3-4 minutes before commencing shaving. This allows time for more water to enter the hair shaft. At this point, the hair and skin are ready for shaving.
Once the skin has been properly prepared, it is necessary to execute the proper shaving technique. The blade should gently glide over the skin surface with minimal pressure. The quality of a shave is measured as the ratio of the amount of hair removed to the amount of skin removed. If the ratio is high, the shave is good. Conversely, if the ratio is low, the shave is poor. The blade should be dragged over each area for shaving only once. If the blade is rubbed multiple times over the same area, the chance for razor burn increases. Any areas that are not shaved as closely as desired should be left for shaving on the following day.
Shaving should occur in parallel strokes, even though the hair may grow in many different directions. The newer multiple blade razors provide for excellent shaving of hairs that demonstrate different skin exit angles. It is also important to rinse the blade after each stroke, to remove hair, skin, and shaving gel debris.
A common dermatologic problem related to shaving is the spread of disease. Bacterial diseases, such as impetigo and MRSA infection, can be spread on a razor blade in addition to viral diseases, such as verruca and molluscum contagiosum. A good razor and shaving cream can help in minimizing skin trauma and the opportunity for infection, but it may be necessary for shaving to be discontinued in infection areas until treatment is complete.
Razor blades can pass bacterial and viral infection to various sites on an individual patient or between family members who all use the same razor. It is best not to share razors for hygiene reasons, but also for optimal blade performance. Blades that are used to shave a male face experience razor wear in a different manner than blades used to shave female legs. Different patterns of blade wear can lead to increased razor burn.
Allowing the razor to dry between uses can minimize the spread of infection. Soaking the razor head and blade in rubbing alcohol for a minute can also decrease spread, but can decrease razor blade life. Patients can put 2 inches of isopropyl alcohol in a jar and let the razor sit in the jar for 60 seconds, remove, and allow to dry, if recurrent infection is a problem.
Special skin areas, such as the female underarms and bikini area, deserve special mention. The underarms are unique in that they are concave, instead of convex, like most other shaved body areas. Likewise, the bikini area requires shaving areas that may be difficult to visualize again with tight concave areas that the razor must reach. There are razors designed for male and female use. Male razors are designed to shave the small curved areas of the face. Female razors are designed to shave the straight long surfaces of the legs and not necessarily the armpits and the groin. It is important to pick a razor that fits nicely in the hand of the user. For people with shaving challenges, it is well worth the money to buy several different handles with a few blades to see which one provides the best shave. Just like many people have a favorite pen, it is also necessary to find that one favorite razor.