Future Challenges of Vitamin D Deficiency: The Impact of Systemic Vitamin D Therapy on Serum Levels and Skin Diseases

In recent years, research on the role of vitamin D in skin diseases has grown, revealing its dose-dependent effects on cell function and its immunomodulatory, antioxidative, and cytoprotective properties. These findings have expanded their use in dermatology. However, the rising incidence of deficiency, linked to reduced sun exposure from indoor lifestyles and cultural practices, underscores the need for further investigation and therapeutic strategies. To review key insights on the systemic use of vitamin D in common immunomodulatory skin diseases, beyond its well-established topical applications. The electronic research of the literature included three databases: MEDLINE, Cochrane, and Google Scholar, as well as other available literature sources. Decreased serum vitamin D levels are observed in psoriasis, vitiligo, and alopecia areata. Systemic vitamin D therapy has shown clinical improvement in psoriasis, vitiligo, and atopic dermatitis, with limited but promising evidence in alopecia areata. It may play a role in managing acne vulgaris, though long-term data remain insufficient. The effects of systemic vitamin D analogs in the clinical treatment of many skin diseases are promising, but further clinical studies are needed.