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> There exists substantial evidence to support that Black skin has a higher transepidermal water loss, variable blood vessel reactivity, decreased skin surface pH, and larger mast cell granules compared with White skin. Although some deductions have been made about Asian and Hispanic skin, further evaluation needs to be done. Differences in water content, corneocyte desquamation, elastic recovery/extensibility, lipid content and skin microflora, although statistically significant, are inconclusive.
https://link.springer.com/article/10.2165/00128071-200304120...
> The thickness of the skin is higher on the cheek compared with the dorsal and ventral forearm, with no ethnic or age-related specificity. We confirm that the sub-epidermal non-echogenic band is a sensitive marker of skin aging, and reveal for the first time that it is less pronounced in African Americans. From OCT images, we bring out evidence that the thickness of the dermal–epidermal junction (DEJ) decreased with age, and was higher in African Americans than in Caucasians. Finally, by comparing US images at 150 MHz with OCT images, we show that papillary dermis thickness can be measured and appears to be quite constant irrespective of age or ethnic group.
https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0846...
> Skin roughness, scaliness and stratum corneum hydration varied significantly in different anatomic areas and age groups. There was no racial variation in skin hydration between any anatomic site, nor significant differences in roughness and scaliness between races, except for the preauricular area. Skin roughness was significantly increased in the aged, compared to the young at the preauricle, volar forearm, lower back, thigh and lower leg. Older women demonstrated significantly more scaling at the preauricle than younger women. Stratum corneum hydration correlated with scaliness. No significant correlation between stratum corneum hydration and skin roughness was observed.