Vitamin D and the Skin: An Update for Dermatologists

Abstract

Vitamin D plays a key role in skeletal and cardiovascular disorders, cancers, central nervous system diseases, reproductive diseases, infections, and autoimmune and dermatological disorders. The two main sources of vitamin D are sun exposure and oral intake, including vitamin D supplementation and dietary intake. Multiple factors are linked to vitamin D status, such as Fitzpatrick skin type, sex, body mass index, physical activity, alcohol intake, and vitamin D receptor polymorphisms. Patients with photosensitive disorders tend to avoid sun exposure, and this practice, along with photoprotection, can put this category of patients at risk for vitamin D deficiency. Maintaining a vitamin D serum concentration within normal levels is warranted in atopic dermatitis, psoriasis, vitiligo, polymorphous light eruption, mycosis fungoides, alopecia areata, systemic lupus erythematosus, and melanoma patients. The potential determinants of vitamin D status, as well as the benefits and risks of vitamin D (with a special focus on the skin), will be discussed in this article.

Increased prevalence of vitamin D deficiency in patients with alopecia areata: a systematic review and meta‐analysis

“…The active form of vitamin D, 1,25(OH) 2 D, has modulatory effects on the innate and adaptive immune system . Vitamin D inhibits the formation of dendritic cells and reduces T‐cell activation.…”

“…The active form of vitamin D, 1,25(OH) 2 D, has modulatory effects on the innate and adaptive immune system. 6 Vitamin D inhibits the formation of dendritic cells and reduces T-cell activation. In addition, vitamin D has been reported to be involved not only in inhibiting Th1 differentiation, but also in developing tolerance to auto-antigens, increasing CD4+ CD25+ regulatory T-cell activity.…”

“…The heterogeneity of the included studies was calculated using the chi‐squared test for heterogeneity (with P < 0.1 indicating statistical significance) and the I 2 statistic for inconsistency. We expected a significant degree of heterogeneity of the included studies because vitamin D synthesis and serum levels can be affected by numerous factors such as the study setting (e.g. latitude, season, amount of sunshine), ethnic differences (e.g.…”

“…Vitamin D is a group of fat‐soluble secosteroids, synthesized in epidermal keratinocytes . As vitamin D from the diet or synthesis in skin is inactive, it is required to be enzymatically converted to its active form, 1,25‐dihydroxyvitamin D (1,25(OH) 2 D).…”

“…[3][4][5] Vitamin D is a group of fat-soluble secosteroids, synthesized in epidermal keratinocytes. 6 As vitamin D from the diet or synthesis in skin is inactive, it is required to be enzymatically converted to its active form, 1,25-dihydroxyvitamin D (1,25 (OH) 2 D). Among the various roles of vitamin D in the human body, the immunomodulation and its impact on the onset and activity of autoimmune diseases have been discussed.…”