ARTICLE: Compromised Skin Barrier and Sensitive Skin in Diverse Populations.

The most important function of the stratum corneum (SC), the uppermost layer of the human epidermis, is the formation of the epidermal permeability barrier. Lipids, particularly ceramides, cholesterol, and free fatty acids, together form lamellar membranes in the extracellular spaces of the SC that limit the loss of water and electrolytes. In addition to preventing water and electrolyte loss, the SC as a permeability barrier prevents the entry of harmful irritants, allergens, and microorganisms into the skin. Disruption of the epidermal barrier leads to skin that is irritated, more reactive, and more sensitive than normal skin. SC thickness, lipid profile, and barrier function vary with different ethnic groups, which is also reflected the differences in prevalence and manifestation of diverse skin conditions related to the skin barrier function such as atopic dermatitis and sensitive skin. In addition to these compromised skin barrier related conditions, we are just now starting to understand the direct and indirect impact of COVID-19 on the skin and how current preventative measures are contributing to skin barrier disorders. Our understanding of various approaches for restoration of skin barrier, especially the role of topically applied mixtures of cholesterol, ceramides, and essential/nonessential free fatty acids (FFAs) allows for the strengthening of the compromised skin barrier and alleviation of symptoms and discomfort associated with skin barrier disorders. Ceramide containing products on the market are commonly available and offer protection and reparative benefits to the skin barrier. J Drugs Dermatol. 20(4 Suppl):17-22. doi:10.36849/JDD.S589C.