We shall now turn our discussion to skin color. Skin color produces as many variations in skin care needs as age. All colors of skin possess melanin, but the differences arise from how the melanin is packaged within the skin. This difference in melanin packaging gives rise to light and dark skin and also to the skin sunburn characteristics. These topics are covered in more detail in the sunscreen chapter; however, here we shall address the unique differences between skin color and skin care product response. Very light skin that does not tan well typically does not respond to injury with pigmentation problems. There may be some transient hypopigmentation, or reduced skin color, especially with skin dryness where the skin does not tan well, a condition medically known as pityriasis alba. Hypopigmentation may also be seen following a traumatic skin injury, especially if the melanocytes have been damaged. However, a burn injury usually results in increased pigmentation, medically known as post-inflammatory hyperpigmentation. This is in contrast to persons with darker skin, to include Asian, Mediterranean, African American, and Hispanic persons, who experience frequent post-inflammatory hyperpigmentation, which is a larger cosmetic concern than wrinkling in these ethnic groups.
Postinflammatory hyperpigmentation is darkening of the skin in response to injury. The injury can be from acne, sunburn, skin disease, irritant contact dermatitis, allgeric contact dermatitis, or a traumatic scratch. Since melanocytes are felt to be an important part of the immune system, it is postulated that this hyperpigmentation is an immune response to skin injury, but the exact reason for this reaction is largely unknown. Thus, products designed for skin of color must be carefully formulated to minimize any skin irritation, since postinflammatory hyperpigmentation is the inevitable result. It may take six months to one year to return the skin to normal color after the injury, which accounts for the tremendous skin lightening product focus in cultures with darker complected
individuals. In order to return the skin to proper color, the extra melanin produced must be phagocytized or consumed by white blood cells and then removed from the skin. More superficial pigmentation can be readily removed while some deeper dermal pigmentation may be permanent.
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 selftanning 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 skin of color. Follicular predilection refers to the presence of disease around the follicle and at the opening of the hair onto the skin surface, known as the follicular ostia. For example, eczema due to dry skin usually occurs evenly over the skin surface in fair complected individuals, but in African American persons, the eczema occurs around the follicular ostia giving the skin a unique goose bump type of appearance. Whether this reaction pattern is due to the increased melanin or the kinky hair is unknown, but this type of eczema is considerably more difficult to treat. Mild skin irritation or full blown irritant contact dermatitis may also be present with this follicular pattern. Thus, problems associated with skin care products or cosmetics may appear differently in skin of color, sometimes confusing the proper diagnosis.