Skin barrier components and keratinocytes

The skin barrier is a complex multi-layered system primarily consisting of the stratum corneum, where keratinocytes differentiate into corneocytes embedded in a lipid-rich extracellular matrix (StatPearls, 2023). This barrier provides essential protection against pathogens, chemical irritants, and ultraviolet radiation while regulating transepidermal water loss (TEWL) to maintain internal homeostasis (Journal of Investigative Dermatology, 2012). Keratinocytes play a central role by synthesizing structural proteins such as filaggrin, loricrin, and involucrin, as well as essential lipids like ceramides, cholesterol, and free fatty acids (PubMed, 2020). Dysregulation of these components is a primary driver of inflammatory skin diseases such as atopic dermatitis and psoriasis, where barrier breakdown allows allergen penetration and triggers chronic immune responses (NIH, 2021). Pharmacological agents like topical corticosteroids, retinoids, and barrier repair creams target these components to restore structural integrity, normalize cell turnover, and reduce inflammation (Clinical, Cosmetic and Investigational Dermatology, 2015). Because this term refers to a broad physiological system rather than a single molecular entity, it is generally considered a therapeutic 'area' or 'system' rather than a specific drug target.

Other names

Epidermal barrierStratum corneum barrierPermeability barrierKeratinocyte-lipid complex

Drugs targeting this system work by occluding the surface to prevent water loss, replenishing essential lipids (ceramides, fatty acids), modulating keratinocyte proliferation and differentiation via nuclear receptors (RAR, VDR), or inhibiting inflammatory cytokines that degrade barrier proteins.