Skin Barrier Compromise: A Central Early Event in Ultraviolet Radiation-Induced Skin Pathogenesis

Ultraviolet radiation (UVR) is a major environmental stressor to the epidermal barrier, extending beyond erythema or photoaging. Emerging evidence reframes barrier impairment as an early and central event, integrating DNA and oxidative injury with inflammatory, immune, and microbial disturbances in a self-reinforcing cycle of fragility. This perspective challenges the traditional view of UVR damage as isolated mechanisms and highlights the need for barrier-focused research. Sunscreens remain essential, and recent formulations now extend beyond optical filtering by incorporating biologically active components such as antioxidants and photolyase that enhance photostability and support DNA lesion clearance. Emerging research also suggests that microbiome-preserving compositions may help maintain commensal balance during UVR exposure. Together, these developments point to a shift toward multifunctional photoprotection, although evidence is still accumulating. This review synthesizes recent advances alongside remaining gaps in the field. By integrating mechanistic evidence on UVR-induced barrier injury, it identifies directions that can support the design of more biologically grounded photoprotective strategies and delineates priority topics for future research.