Lee S, et al. - Authors presented the differences of the mean serum 25-hydroxyvitamin D level and prevalence of vitamin D deficiency between alopecia areata (AA) patients and non-AA population. Lower serum 25-hydroxyvitamin D level was seen in the AA subjects and compared to non-AA controls, vitamin D deficiency was highly prevalent. Therefore in AA patients, vitamin D deficiency ought to be assessed. Moreover, for AA patients with vitamin D deficiency, consideration of nutritional supplementation of vitamin D or topical vitamin D analogues was suggested.