Background: Alopecia areata (AA) is an autoimmune disease involving the inflammation of hair follicles. In many autoimmune diseases, inadequate levels of vitamin D have been reported. We aimed to determine the association between vitamin D levels and AA.
Methods: In this case-control study, 50 AA patients and 50 controls were assessed regarding serum levels of 25-hydroxy vitamin D [25-(OH)-D3]. The levels of 25-(OH)-D3 were classified as deficient ( < 20 ng/ml), insufficient (20 to 30 ng/ml), and sufficient ( > 30 ng/dl). The severity of the disease was scored according to the Severity of Alopecia Tool (SALT).
Results: The serum level of 25-(OH)-D3 was significantly lower in AA cases compared with the control group. Patients with the totalis or universalis pattern of hair loss had lower levels of 25-(OH)-D3 relative to patients with the patchy or ophiasis type of AA. Moreover, severe cases showed significantly lower levels of vitamin D relative to mild and moderate cases. We found a significant inverse association between 25-(OH)-D3 level and age. We found no association between serum levels of 25-(OH)-D3 and gender, disease duration, disease recurrence, nail involvement, or positive family history of AA.
Conclusion: AA patients had lower serum levels of vitamin D, though this did not contribute to the severity or duration of disease or pattern of hair loss. More studies are required to evaluate the role of vitamin D supplementation in the pathophysiology of AA.