Alopecia Areata and malignancies: uncertainties clarified by a large-scale population-based study

The association of AA with malignancies has been a scope of controversy as the current literature is highly inconsistent in this regard. To evaluate the association between AA and hematological malignancies (HMs) and solid malignancies (SMs) using a large-scale, real-life computerized database. A cross-sectional study was conducted to compare the prevalence of HMs and SMs among patients with AA relative to age-, sex-, and ethnicity-matched control subjects. Chi-square and t-tests were used for univariate analysis, and a logistic regression model was used for multivariate analysis. The study included 51,561 patients with AA and 51,410 controls. AA was significantly associated with HMs (adjusted OR, 1.27; 95% CI, 1.07-1.51; P = 0.006). This association was more robust among patients with late-onset AA (≥ 50 years; OR, 1.33; 95% CI, 1.04-1.71; P = 0.025). On the other hand, AA was not found to be significantly associated with SM (adjusted OR, 0.97; 95% CI, 0.88-1.06; P = 0.487), excluding among patients with alopecia totalis and universalis (OR, 2.10; 95% CI, 1.03-4.27; P = 0.036). In a granular analysis including 5 HMs and 18 SMs, non-Hodgkin lymphoma was the only malignancy that proved positively associated with AA (adjusted OR, 1.32; 95% CI, 1.03-1.69; P = 0.028). AA is associated with HMs but not SMs. Further research is warranted to validate our observations in other study cohorts.