Editor’s note: This article originally was published in the September 2006 issue of Cosmetics & Toiletries magazine, and has been reprinted with permission.
The approach to ethnic skin care and treatments can be challenging. This mainly is because ethnic skin has a propensity to develop hyperpigmentation—or a darker discoloration of the skin—or hypopigmentation—a lighter discoloration of the skin—when the appropriate products or treatments are not utilized. To further examine the challenges of ethnic skin care, one must first define ethnic skin.
Defining ethnic skin
The Fitzpatrick Skin Type classification often is used to define ethnic skin. This scale ranges from type I (ivory white skin) to type VI (dark brown skin) and identifies skin type based on its reaction to UV light. Skin of color can be classified as skin types IV–VI.
Biology of ethnic skin
Pigmentation in the skin is determined at the cellular level. Melanocytes are the cells that make melanin, or pigment, in the skin. Melanosomes are the packages of melanin produced by the melanocytes. Pointy extensions of the melanocytes then transfer melanosomes into the keratinocytes.
Although there may be some variation in the number of melanocytes among races, this difference is not striking. In all races, there are approximately 2,000 epidermal melanocytes/mm2 on the head and forearms, and 1,000 epidermal melanocytes/mm2 on the rest of the body. These differences are present at birth.1 Thus, all people have the same total number of melanocytes; it is the distribution of melanosomes in the keratinocytes that correlates with skin color. In white skin—typically types I–III—melanosomes are small and aggregated in complexes. In black skin—types V and VI—there are larger melanosomes that are distributed singly within keratinocytes.2
The role of melanin in the skin is to absorb and scatter energy from UV light to protect the epidermal cells from damage. Melanin provides considerable protection from sun damage, and the degree of protection corresponds directly to the degree of pigmentation. This sun protection offers significant prevention of photo-aging, which is one of the primary cosmetic concerns in Fitzpatrick skin types I–III.
The cosmetic advantage of skin types IV–VI is an increased protection from photo-aging. However, the cosmetic disadvantage of skin of color is its propensity to develop hyperpigmentation or hypopigmentation, which ethnic clients frequently experience and are most concerned about preventing.3 Essentially, any inflammation or injury to the skin can be followed immediately by an alteration in pigmentation.
Hyperpigmentation in ethnic skin
Any ingredient that has a potential to cause significant irritation or dryness when applied to the skin can cause pigment alteration in ethnic skin. Although hypopigmentation can occur, hyperpigmentation is most common. The patients at greatest risk are those with dry, sensitive skin. The most common topical treatments associated with pigment alterations include benzoyl peroxide, retinoids, salicylic acid and glycolic acid. Additionally, in predisposed clients, hydroquinone can be irritating and can lead to hyperpigmentation. Typically, individuals first report dryness and irritation. In more severe cases, this is followed by redness and even superficial erosions.
In skin types I–III, if any reaction occurs, the skin typically will return to normal once use of the product is discontinued. Ethnic skin differs from the lighter skin types because, in these clients, dryness and irritation frequently are followed by postinflammatory hyperpigmentation. In predisposed individuals, hyperpigmentation usually develops within one to two weeks and can last for several months. However, it is important to note that pigment alterations are rare when benzoyl peroxide, retinoids, salicylic acid and glycolic acid are utilized correctly in ethnic skin. Clients with ethnic, dry, sensitive skin can avoid pigment alterations by using products that are formulated in emollient-based vehicles or with lower concentrations of the active ingredient.