Determination of serum 25-hydroxyvitamin D levels in patients with alopecia areata and their comparison with levels in healthy controls: A cross-sectional study.

Background: Alopecia areata (AA) has been postulated to be an autoimmune disease affecting the hair follicles. Because vitamin D receptors are present in the immune system and hair follicles, vitamin D has been hypothesized to affect the disease.

Objective: The aim of this study was to determine serum 25-hydroxyvitamin D levels and the percentage of vitamin D deficiency in AA patients and compare them with those in healthy controls in a Philippine tertiary hospital.