Vitamin D Level in Alopecia Areata

Alopecia areata (AA) is an immune-mediated disease in which autoantigens play an important part in activating T-lymphocytes. Vitamin D has been associated with various autoimmune diseases, and Vitamin D receptors are strongly expressed in hair follicles and their expression in keratinocytes is necessary for the maintenance of the normal hair cycle.

The aim of this study was to find the association between Vitamin D level and AA.

This was a hospital-based cross-sectional study in which 50 patients with clinically and trichoscopically diagnosed AA cases, and 35 healthy age- and sex-matched controls were studied in summer months. Blood samples were taken from both cases as well as controls and samples were immediately processed by centrifugation (4000 rpm) at room temperature. Plasma 25-hydroxyvitamin D (25(OH)D) was analyzed by chemiluminescence method. A deficiency in Vitamin D was defined as serum 25(OH)D concentrations <30 ng/ml.

The mean body mass index in cases was 20.96 ± 1.91, whereas in controls, it was 21.37 ± 1.70 (P = 0.31). The mean serum 25(OH)D levels of AA patients was 16.6 ± 5.9 ng/ml, whereas in control group, the mean level was 40.5 ± 5.7, the difference being statistically significant (P < 0.001). A significant negative correlation was found between severity of alopecia tool score and Vitamin D level (P < 0.001; r = -0.730) and also between the number of patches and Vitamin D level (P < 0.001, r = -0.670).

In our study, we found that the levels of 25(OH)D were low in AA patients when compared to healthy controls. Furthermore, there was a significant negative correlation between the levels of serum Vitamin D and severity of AA. Thus, the study suggests the role of Vitamin D in pathogenesis of AA and hence a possible role of Vitamin D supplementation in treatment of same.

Our study was limited by the lesser number of patients and lack of therapeutic trial of Vitamin D for these patients.