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j. Soc. Cosmet. Chem., 47, 229-240 (July/August 1996) A comparison of black and white skin using noninvasive methods A. G. WARRIER, A. M. KLIGMAN, R. A. HARPER, J. BOWMAN, and R. R. WICKETT, College of Pharmacy, University of Cincinnati, 3223 Eden Avenue, Cincinnati, OH 45267-0004 (A. G. W., R.R. W. ), Department of Dermatology, University of Pennsylvania, 422 Curie Boulevard, Philadelphia, PA 19104-6142 (A.M.K.), and Hill Top Research, Inc., P.O. Box 429501, Cincinnati, OH 45242 (R.A.H., J.B.). Accepted for publication July 31, 1996. Synopsis Differences in the characteristics of black and white skin were investigated in thirty black and thirty white female subjects between the ages of 18 and 45, using noninvasive methods. Parameters studied included transepidermal water loss (TEWL), electrical capacitance, skin pH, elasticity, dryness/scaling, and skin surface microflora. TEWL was found to be significantly lower on the cheeks and legs in blacks as compared to whites. Black facial skin exhibited higher elasticity and electrical capacitance values. The desquamation index was found to be higher in white subjects on the cheeks and forehead, whereas dryness scores were significantly higher for blacks on the legs. Whites had slightly higher pH than blacks. Overall density of Propionibacterium acnes was found to be higher in blacks. No significant differences were found in the aerobic skin surface microflora. Results from the present study will help gain a better understanding of the variations in characteristics of black and white skin. INTRODUCTION Recent studies have revealed that the differences between the skin of whites and blacks extend well beyond the degree of melanin pigmentation. Yet, comparative studies of the structural and physiologic characteristics are sparse, limited, and sometimes contradic- tory. Studies have shown that though the black and white stratum corneum (SC) are equal in thickness (1), black SC contains more compact layers of corneocytes and exhibits greater resistance to cellophane tape stripping than Caucasoid SC (2). Increased levels of epi- dermal lipids have also been reported for blacks (3). Though it is generally believed that black skin is a more effective barrier to certain chemicals and irritants (2,4,5), higher TEWL and SC water content due to surfactant barrier damage have been reported (6,7). On the contrary, increased electrical resistance (8,9) and decreased inflammatory re- sponses (2,4,5) have been demonstrated in blacks as compared to whites. Investigations 229