Oral and topical vitamin D treatment strategies in psoriasis.

Psoriasis is a prevalent skin disorder affecting approximately 2-3% of the population in the USA. Its complex and varied presentations necessitate a diverse range of available therapeutic options. While topical corticosteroid therapy is conventionally employed as first-line treatment, long-term usage increases the risk of adverse events, prompting the consideration of alternatives including steroid-sparing agents such as vitamin D. In this article, we review literature from topical and oral vitamin D trials for the treatment of psoriasis. Topically, vitamin D analogues have been well established as an effective long-term treatment, particularly when used in combination with other therapies. Moreover, combination therapy with immunomodulators such as apremilast and methotrexate has shown promise as well. Conversely, oral vitamin D supplementation trials have yielded more inconsistent results, with some supplementation clinical trials showing significant psoriasis resolution and others showing no significant changes in psoriasis outcome. Vitamin D deficiency status, seasonal variation and body mass index were factors that may have modulated the therapeutic effect of vitamin D supplementation. Further study combining vitamin D supplementation with pre-existing treatments may also augment the effect of monotherapy. Studies on the synergistic effects of combination therapies with oral vitamin D or the development of foam-based or microneedle drug delivery systems may be promising next steps.