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Variations in Pigmentation and Ultrastructural Skin Differences Among Ethnic Groups
By: Rupa Pugashetti, MD, Santa Clara Valley Medical Center, and Howard I. Maibach, MD, University of California School of Medicine
Posted: September 1, 2010, from the September 2010 issue of Cosmetics & Toiletries.
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Tristimulus colorimeter: Alaluf et al. examined the impact of epidermal melanin in different ethnic skin types on the objective measurements of human skin color22 taken by a tristimulus chromameter. L*, a*, b* measurements were made in European, Mexican, Chinese, Indian and African subjects. Overall, darker skin types tended to have lower L* values, higher a* values and higher b* values, compared with constitutively lighter skin types. Results demonstrated that total epidermal melanin is the primary determinant of L* values. Melanosome size also had a significant influence on L* values, and larger melanosomes are associated with a darker skin color, as previously discussed. Based on the strength of correlations observed in this study, epidermal melanin content still appears to play a greater role in determining skin color than melanosome size.
Many advances have been made in understanding the genetic, molecular and cellular differences underlying normal variation in human skin pigmentation. However, further studies must be carried out to investigate the genetic pathway underlying melanin synthesis, the role of genetic variation in epidermal pigmentation, and to elucidate differences in skin pathophysiology among humans from different ethnic backgrounds. Understanding the differences in pigmentation and skin structure and function among varying ethnic types can assist chemists and formulators in developing products to target the different needs of diverse skin types. Reproduction of the article without expressed consent is strictly prohibited.
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*Revised with permission from: R Pugashetti and H Maibach, Pigmentation in Ethnic Groups, ch 52 in Aging Skin, MA Farage, KW Miller and HI Maibach, eds, New York: Springer (2010) pp 503–508