Abstract

Keratin is a structural protein essential for the integrity, mechanical strength, and protective functions of the skin and its appendages. In dermatology, keratins are particularly important in epidermal differentiation, maintenance of the skin barrier, wound repair, and the development of hair and nails. These proteins form intracellular intermediate filaments that provide resilience to epithelial cells and help tissues withstand mechanical stress. Different keratin isoforms are expressed according to epithelial cell type and differentiation stage, making keratin expression useful in understanding normal skin physiology and pathological changes. Mutations in keratin genes can cause inherited skin fragility disorders, including epidermolysis bullosa simplex, while abnormal keratinization contributes to several hyperkeratotic conditions. Keratin-associated pathways are also relevant to inflammatory skin diseases, tissue regeneration, and biomaterial development. This review summarizes keratin structure, biological functions, dermatological disorders, diagnostic significance, and emerging therapeutic applications, emphasizing its importance in maintaining cutaneous health and guiding future dermatological research.