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Historically, people in many societies have searched for methods to restore youthful appearance and rejuvenate aging skin. Stories recount the efforts of ancient Chinese emperors and Spanish explorers to seek mythical substances and supernatural powers thought to have the ability to reverse the aging process. During the Dark Ages, European alchemists spent endless hours investigating magical methods for prolonging life and restoring youthful beauty. These beliefs have become rooted in modern-day society, as people continue to seek assistance for facial skin rejuvenation from healthcare professionals all over the world. In fact, because of the unbounded interest in this field and the aging population, more options now exist than ever before for reversing cutaneous changes caused by long-term exposure to sunlight. More recently, the spectrum of skin issues for which these methods have been utilized has expanded past the treatment of photoaging to include many skin problems more common in youth such as pigmentary disorders and acne scarring.
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The population of the United States is not only aging, but also becoming more ethnically diverse. Data from the 2000 census revealed that 31% of the U.S. population is of ethnic background, and this statistic is expected to reach 50% within just a few years.1 Although, Caucasian skin is more prone to ultraviolet light injury, ethnic skin also exhibits characteristic changes of photoaging. In 2003, racial and ethnic minorities accounted for 20% of all cosmetic procedures, and dermatologists and cosmetic surgeons likely will see an increasing influx of patients with darker skin types seeking rejuvenation treatment for aging skin and other cutaneous problems.2 Hence, it is imperative to understand the differences in techniques, results and side effects in using these procedures on ethnic skin as compared to lighter colored skin types.
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In this chapter, we will discuss these considerations in the context of ablative skin resurfacing, which can be accomplished using lasers, chemical peels, and microdermabrasion. Techniques and possible adverse reactions for these modalities in the treatment of ethnic and darker skin types will be considered.
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ETHNIC SKIN—DEFINITION
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Skin color in different ethnic groups varies dramatically from dark to light, as exemplified by central African and northern Scandinavian individuals, respectively, despite the fact that the density of melanocytes in the skin of these two skin types is identical. Numerous investigators have studied the biological basis of human skin color variation over the years. The intrinsic coloration is determined by the amount and type of melanin in the skin. However, an equally important determinant of skin color is the variation in the quantity, packaging, and distribution of epidermal melanin within keratinocytes of different ethnic groups. It is well documented that the melanosomes within keratinocytes of dark skin are distributed individually in the cytosol, predominantly over the nucleus, whereas the melanosomes within keratinocytes of light skin are clustered together in membrane-limited groups of two to eight melanosomes, also in the ...