Screening of thyroid function and autoantibodies in patients with alopecia areata: A systematic review and meta-analysis

Background: Several studies have reported associations between alopecia areata and diverse thyroid diseases. Objective: To investigate the odds ratio and prevalence rate of thyroid dysfunction and autoimmune thyroid diseases in patients with alopecia areata. Methods: A systematic review of the studies published before March 20, 2018, was performed by using the MEDLINE, Embase, Web of Science, and Cochrane Library databases. The clinical and laboratory findings associated with thyroid dysfunction and autoimmunity were extracted for quantitative analysis. Results: A total of 50 studies were analyzed. Patients with alopecia areata had higher odds of abnormal findings on thyroid function tests, thyroid dysfunction, positive thyroid autoantibodies, and autoimmune thyroid diseases. Moreover, their prevalence rate was much higher than that in the general population. Limitations: The heterogeneity in baseline characteristics and outcome reporting across the studies. Conclusion: Current evidence suggests that thyroid dysfunction and autoimmune thyroid diseases are more prevalent in patients with alopecia areata. Clinicians may be encouraged to screen for the associated signs and symptoms to achieve better outcomes.