History of atopy or autoimmunity increases risk of alopecia areata

Background: The association between a history of atopy or autoimmune diseases and risk of alopecia areata (AA) is not well established. Objective. The purpose of this study was to use the National AA Registry database to further investigate the association between history of atopy or autoimmune diseases and risk of AA. Methods. A total of 2613 self-registered sporadic cases (n = 2055) and controls (n = 558) were included in this analysis. Results: Possessing a history of any atopic (odds ratio = 2.00; 95% confidence interval 1.50-2.54) or autoimmune (odds ratio = 1.73; 95% confidence interval 1.10-2.72) disease was associated with an increased risk of AA. There was no trend for possessing a history of more than one atopic or autoimmune disease and increasing risk of AA. Limitations. Recall, reporting, and recruiting bias are potential sources of limitations in this analysis. Conclusion: This analysis revealed that a history of atopy and autoimmune disease was associated with an increased risk of AA and that the results were consistent for both the severe Subtype of AA (i.e, alopecia totalis and alopecia universalis) and the localized subtype (ie, AA persistent). (J Am Acad Dermatol 2009;61:581-91.)