Racial (ethnic) differences in skin properties may explain racial disparities seen in dermatologic disorders and the feeling of many consumers that skin care is biased toward the treatment needs of the white-skinned peoples of Europe and North America. The current experimental human model for skin, however, is largely based upon physical and biochemical properties known about white skin. Thus, anatomical or physiological properties in skin of different races that may alter a disease process or treatment of that disease are not being considered.
While scientists have investigated racial differences in skin physiology, the amount of data obtained by objective methods is minimal. Additionally, the data are often confusing and contradictory.
In our review of the objective data available in differentiating skin of several ethnicities, we found both cohesive and conflicting data in the realms of transepidermal water loss, water content, corneocyte variability, blood vessel reactivity, skin biomechanics, pH gradient, lipid content, surface microflora and mast cell granules.
Transepidermal water loss (TEWL) is the most studied objective measure in defining differences between the skin of different ethnicities. TEWL has been used as a method of assessing the skin’s ability to maintain an effective barrier against loss of body fluids and absorption of externally applied substances. Current literature defines TEWL as the total amount of water vapor loss through the skin and appendages under non-sweating conditions.