Alopecia areata (AA) is a T cell-mediated autoimmune disease that causes inflammation around anagen-stage hair follicles. Insufficient levels of vitamin D have been implicated in a variety of autoimmune diseases. Previous reports have described the effects of vitamin D on hair follicles.
To evaluate the status of vitamin D in patients with AA, and the relationship between vitamin D levels and disease severity.
A cross-sectional study of 86 patients with AA, 44 patients with vitiligo and 58 healthy controls was conducted. The serum vitamin D levels of the study group were determined by liquid chromatography/tandem mass spectrometry.
Serum 25-hydroxyvitamin D [25(OH)D] levels in patients with AA were significantly lower than those of the patients with vitiligo and the healthy controls (P = 0·001 and P < 0·001, respectively). The prevalence of 25(OH)D deficiency was significantly higher in patients with AA (91%) compared with patients with vitiligo (71%) and healthy controls (33%) (P = 0·003 and P < 0·001, respectively). Furthermore, a significant inverse correlation was found between disease severity and serum 25(OH)D level in patients with AA (r = −0·409; P < 0·001).
Deficient serum 25(OH)D levels are present in patients with AA and inversely correlate with disease severity. Accordingly, screening patients with AA for vitamin D deficiencies seems to be of value for the possibility of supplementing these patients with vitamin D.