The Diversity of Skin Characteristics

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Skin performance differs in various racial and ethnic groups even though there are many similarities. These unique differences provide opportunities for skin care product development to address these subtle differences. This column examines common questions and some of the controversies regarding physiologic differences in skin between White, African American, and Hispanic individuals.

Are there differences in the skin barrier between ethnicities?

The difference in skin barrier between ethnicities is somewhat controversial because there is a great deal of interindividual variation regardless of ethnicity. Most people possess a more robust skin barrier in more temperate climates and a less robust skin barrier in cold and low-humidity environments. Ambient humidity is the most important variable to control when examining ethnic skin differences. Usually, transepidermal water loss measurements are used as the best indicator of skin barrier condition; however, acclimating to the environment in which the measurements are taken is key to accuracy. Most reports hold that skin of African American individuals possesses higher transepidermal water loss than skin of White individuals, although the opposite has also been reported (but less frequently). Higher transepidermal water loss is an indicator of poorer barrier function in African American individuals than in White individuals.

Do differences exist in skin moisturization between ethnicities?

Skin moisturization is usually measured through a technique known as corneometry. Corneometry is an indirect measurement of the water content of the skin through skin conductance. Skin conductance has been reported to be higher in African American and Hispanic individuals than White individuals. This means that skin of African American and Hispanic individuals is naturally better moisturized than skin of White individuals.

What are the physiologic differences in skin lipid content?

Skin lipids are an important component of skin barrier function and are found in the intercellular space between the corneocytes. Absent and/or defective intercellular lipids are found in xerotic eczema and atopic dermatitis but may be induced by excessive surfactant and water exposure. Lipid content is higher in skin of African American individuals than skin of White individuals. In addition, the ratio of ceramides, cholesterol, and free fatty acids is also different.

Do ceramide levels vary between ethnicities?

Ceramides are the first substance synthesized when the skin barrier has been damaged; thus, they are essential to barrier repair. Ceramide levels are 50% lower in skin of African American individuals compared with skin of White individuals. This could explain why African American individuals report a higher incidence of sensitive skin than White individuals. It could also explain why eczema and atopic dermatitis are more prevalent in African American individuals than White individuals.

Does stratum corneum desquamation vary between ethnicities?

Stratum corneum desquamation does vary between ethnicities. Desquamation in skin of African American individuals is 2.5 times greater than desquamation in skin of White individuals. It is often said that skin of African American individuals appears ashier than skin of White individuals. This observation could be due to increased desquamation but also due to the pigment in the desquamating skin scale. Desquamated skin in African American individuals appears brown, but when an air interface is introduced between the skin and the skin scale, the skin scale appears gray and thus resembles ash. This makes the desquamating scale more visible compared with skin scale of White individuals where the white scale is cast against a white background. This makes emollience more important in skin of African American individuals, as emollients are oily substances able to intercalate between the desquamating corneocytes and smooth down the skin scale temporarily until sloughing occurs.

What are the skin structural differences between different ethnicities?

There are other structural differences in skin between African American and White individuals. The stratum corneum is more compact in skin of African American individuals than in skin of White individuals, and the dermis has more closely stacked smaller collagen fiber bundles with surrounding ground substance in skin of African American individuals.

Key Takeaways

These observations are important because they allow the dermatologist to customize skin care recommendations for cleansers and moisturizers uniquely for the skin needs of each ethnicity. However, it is probable there is more variation between individuals in the same ethnic group rather than between ethnic groups as a whole. Nevertheless, these observations are important because they can explain differing skin needs among various ethnicities.

Zoe Diana Draelos, MD, is a consulting professor of dermatology at Duke University School of Medicine in Durham, North Carolina, and Dermatology Times’ editor in chief emeritus.