2006 ANNUAL SCIENTIFIC SEMINAR 407 SPECIAL CONSIDERATIONS IN THE TREATMENT OF ETHNIC SKIN Andrew F. Alexis, M.D. Department of Dermatology, St. Luke)s-Roosevelt Hospital, 1090 Amsterdam Avenue, # l lB, New Yhrk, NY 10025 andrew.a!exis@columbia.edu Introduction: Ethnic skin or "skin of color" refers to the broad range of skin types and complexions that characterize individuals of African, Asian, Latino, and Middle Eastern descent. Differences in structure, function, and cultural practices in individuals with ethnic skin contribute to variations in the prevalence and clinical presentation of numerous skin conditions. Understanding these differences is paramount in the treatment of ethnic skin, especially in the context of cosmetic skin care. In particular, numerous cosmetic procedures can be associated with disfiguring complications when the nuances of treating pigmented skin are not taken into consideration. These complications include, but are not limited to, dyspigmentation, keloid scarring, and thermal injury. Special considerations in the performance of chemical peels, laser treatment, and cosmetic surgery will be discussed. Moreover, differences in cosmetic needs and concerns in ethnic skin populations will be addressed. Structural and Functional Differences: A number of structural differences between darkly pigmented skin and fair (Caucasian) skin have been reported. Most notably, skin of color is characterized as having increased epidermal melanin (produced by melanocytes), which is packaged within melanosomes that are larger, more numerous, and more dispersed throughout the epidermis. 1 In addition, the rate of degradation of melanosomes is slower in darkly pigmented skin. 2 Other reported structural differences include, an increased number of cell layers in the stratum corneum, increased stratum corneum lipid content, and larger, more numerous fibroblasts in the dermis. These structural features have a number of functional implications. First, skin of color is less susceptible to photodamage from ultraviolet (UV) light compared to Caucasian skin given the protective effect of melanin. Second, labile melanocyte responses to injury or inflammation often lead to dyspigmentation in ethnic skin, such as postinflammatory hyper- and hypo- pigmentation. Third, dermal injury is associated with a greater risk of keloids or hypertrophic scarring as a result of fibroblast reactivity. Racial differences in the structure of the hair follicle and hair shaft include the presence of curved hair follicles and spiral shaped hair shafts in blacks. On cross-section, African or "black" hair is elliptical whereas Asian hair is round, while Caucasian hair is intermediate. 3 These differences in hair structure may contribute (at least in part) to the increased prevalence of certain hair and scalp disorders in African­ Americans such as pseudofolliculitis barbae, acne keloidalis nuchae, and dissecting cellulitis. Treatment Considerations: The above structural and functional characteristics have numerous implications in the treatment of ethnic skin. In particular, procedures that induce epidermal or dermal injury should be performed with caution to minimize the risk of dyspigmentation and hypertrophic scarring or keloid formation. Therefore, resurfacing procedures, such as chemical peeling and microdermabrasion should be superficial in nature (limited to the epidermis and superficial papillary dermis). Moreover, concomitant therapies that may increase the depth of resurfacing, such as topical retinoids, should be restricted these agents are typically discontinued at least 1 week before a resurfacing procedure. Despite these limitations, both chemical peels (using salicylic acid and glycolic acid) and microdermabrasion, can be performed safely in darkly pigmented skin.45 While photodamage and wrinkles are leading indications for resurfacing procedures in light skinned individuals, postinflamrnatory hyperpigmentation, acne, and melasma are the most common reasons for which chemical peels are performed in dark skinned ethnic groups (in the author's experience).

408 JOURNAL OF COSMETIC SCIENCE Laser hair removal, which involves the targeting of the melanin-rich hair follicle, must also be performed with special considerations in order to prevent absorption of laser light by epidermal melanin. Potential complications of laser hair removal and other laser procedures include dyspigmentation, thennal injury, and scarring. As such, the appropriate selection oflaser settings is paramount in the treatment of ethnic skin and these should be tailored to the patient's skin type. Currently, the long-pulsed 1064nm Nd:YAG and 810 nm diode lasers can be used safely for hair removal in darker skin and are commonly used in the treatment of pseudofolliculitis barbae. 6 Given the importance of even skin tone among darkly pigmented ethnic groups, bleaching agents containing hydroquinone or kojic acid are commonly prescribed to treat hyperpigmentation in skin of color. Postinflammatory hyperpigmentation secondary to acne is the leading cause of dyspigmentation in the author's experience. Therefore, bleaching agents and chemical peels are often incorporated into the treatment of acne in ethnic skin. Conclusion: Understanding the unique structural and functional characteristics of pigmented skin is essential in the cosmetic treatment of dark skinned ethnic populations. Special care must be taken to limit epidermal and dermal injury in ethnic skin in order to minimize dyspigmentation and hypertrophic or keloid scarring. With appropriate care, chemical peels, microdennabrasion, and various laser procedures can be performed safely and effectively in skin of color. 1 Richards G.M. Oresajo C.O. Halder RM. Structure and function of ethnic skin and hair. Dermatol Clin 21: 595-600 (2003) 2 Bolognia J.L. Orlow S.J. Melanocyte Biology. In: Bolognia J.L. Jorizzo J.L. Rapini R.P. et al. (eds) Dermatology. New York: Mosby, 2003, pp:935-946. 3 Richards G.M. Oresajo C.O. Halder RM. Structure and function of ethnic skin and hair. Dermatol Clin 21: 595-600 (2003) 4 Grimes P.E. The safety and efficacy of salicylic acid chemical peels in darker racial-ethnic groups. Dermatol Surg 25 (1): 18-22 (1999) 5 Hurley M.E., Guevara LL. Goanzales RM. Pandya A.G. Efficacy of glycolic acid peels in the treatment of melasma.Arch Dermatol 138(12): 1578-1582 (2002) 6 Battle E.F. Jr., Hobbs L.M. Laser therapy on darker ethnic skin. Dermatol C/in 21(4): 713-23 (2003)