Background: Alopecia areata (AA) is an autoimmune disease, based on the response to local and/or systemic corticosteroid treatment. The role of vitamin D in the pathogenesis of immune/autoimmune mediated diseases has been widely investigated.

Objectives: To investigate a possible association between serum 25-hydroxyvitamin D levels and alopecia areata.

Methods: The study included 23 patients diagnosed with AA followed at our outpatient clinic during the period March 2010 to May 2011, as well as a control group matched for age and gender. All subjects underwent a complete work-up and medical examination, anthropometric measurements and laboratory tests. Laboratory tests included complete blood count, C-reactive protein (CRP), and vitamin D levels.

Results: Mean CRP values were significantly higher in the AA group than the control group (1.1 ± 0.7 mg/dl vs. 0.4 ± 0.8 mg/dl, P < 0.05). Vitamin D levels were significantly decreased in the AA group (11.32 ± 10.18 ng/ml vs. 21.55 ± 13.62 ng/ml in the control group, P < 0.05). Multivariate analysis showed that CRP (odds ratio 3.1, 95% confidence interval 2.6–4.2, P = 0.04) and serum vitamin D levels < 30 ng/ml (OR 2.3, 95%CI 2.2–3.1, P = 0.02) were associated with AA. 

Conclusions: We found a significant correlation between AA and vitamin D deficiency. Vitamin D deficiency can be significant risk factor for AA occurrence.