It makes intuitive sense to believe that skin properties are different among ethnic groups. Therefore, how to address dermatological issues would be more effective when these differences are taken into account. As the physiological properties of skin differ widely among ethnic groups, it is therefore not surprising that given the same external environment, skin conditions such as dry skin or hyperpigmentation can be more problematic for some than others. According to research done by Dr. Naissan O. Wesley, racial differences in skin have been minimally investigated by objective methods and the data are often contradictory. Additionally, doctors from Stanford University Medical Center at the Institute for Stem Cell Biology and Regenerative Medicine and Hagey Laboratory for Pediatric Regenerative Medicine have found that many early studies on ethnic skin to be on a small scale. Most studies historically have been on Caucasian skin.
More recent investigations have stressed the use of objective measurements to accurately report racial differences in skin properties. These have included transepidermal water loss, water content, ceramide level, and skin reactivity. Studies focusing on the ability for skin to maintain moisture have used transepidermal water loss, which has been defined as only the total amount of water vapor loss through the skin when there is no sweat gland activity, as the primary metric for evaluation. Derrick Wan MD reviewed prior studies and believes that these prior studies show that Asian skin has the poorest barrier function upon mechanical challenge.
In another study conducted by Jean Paul de Rigal, Ph.D., skin discoloration have been found to increase with age in skin rich with melanin. In this study, 387 women of age 20-90 of different ethnic backgrounds were assessed for skin color and color heterogeneity (122 African Americans, 120 Chinese, 81 Caucasians, and 64 Hispanics). Numerical measurements of skin color were conducted using a device that diffuses light in a spherical manner around the face and allows for color measurements without any shadows. Research data showed that skin color was most diverse and uneven in ethnic skin where African American skin had the most uneven skin color, followed by Hispanics and Asians. Caucasians showed the least skin color variability.These findings have important implications for the future development of skin care and treatment. Different skin types have different abilities to recover from external insults, absorb topical therapeutic agents, and to maintain moisture under various physiological conditions. Hence, skin care must factor these differences to be most effective.
References:
American Journal of Clinical Dermatology. 2003;4(12):843-60.Journal of Clinical Aesthetic Dermatology. 2014 Jun; 7(6): 25–32. Moisturizing Different Racial Skin Types
Journal of Investigative Dermatology. 1974 Jun; 62(6):563-8. Cell layers and density of Negro and Caucasian stratum corneum. Weigand DA, Haygood C, Gaylor JR
Journal of American Academy of Dermatology. 2002 Feb; 46(2 Suppl Understanding): S41-62. Skin of color: biology, structure, function, and implications for dermatologic disease. Taylor SC
Rothman S, editor. Physiology and Biochemistry of the Skin.2nd ed. University Press; Chicago, IL: 1954. p. 741.