Despite the increased incidence of common and viral infections in individuals with AA, this study found no clinically significant association between AA and increased risk for infections.
Alopecia areata (AA) is a prevalent autoimmune disorder that commonly occurs during early adulthood. Previous studies have highlighted a complex association between autoimmunity and infections. This population-based cohort study, published in Clinical and Experimental Dermatology, evaluated whether AA increases the risk or provides protection against common infections.
The investigators acquired data from the Research and Surveillance Centre Database of the UK Oxford-Royal College of General Practitioners. The study compared a total of 10,391 AA cases with 41,564 propensity-matched controls. The infections compared between the disease and control groups included genital and herpes infections, respiratory, gastrointestinal, urinary tract, and skin infections.
The study findings suggest that the incidence of both viral and common infections, measured per 100 person-years, was slightly increased in AA cases compared to the controls. The authors observed positive associations in adjusted analysis for gastrointestinal, skin, herpes simplex, and respiratory tract infections; composite outcomes; and viral infections. After eliminating controls, who did not have a recent general practitioner consultation, the authors found no association between common and viral infections and AA. The authors also found no evidence to support the association between the negative control outcome of lower limb fracture and AA. Hence, there is no clinical significance of the increased incidence of viral and common infections in individuals diagnosed with AA. The negative control analysis supports the assumption that individuals with AA are more likely to consult the general practitioner for infections instead of having any true association between the two parameters.
In summary, this population-based cohort study did not find any clinically significant association between the incidence of viral and common infections and AA. Further studies may evaluate the contribution and clinical significance of other factors, including pharmacological formulations, in increasing the risk of infections in individuals diagnosed with AA.
Andrew G Messenger, Matthew Harries, Abby E Macbeth, Wing Sin Chiu, Susan Holmes, Christos Tziotzios, Simon de Lusignan, Alopecia areata and risk of common infections: a population-based cohort study, Clinical and Experimental Dermatology, 2022; llac106, https://doi.org/10.1093/ced/llac106