Hidradenitis suppurativa is associated with acne keloidalis nuchae: a population-based study.

The association between acne keloidalis nuchae (AKN) and hidradenitis suppurativa (HS) is yet to be investigated. To determine the link between AKN and HS using a large computerized health maintenance database. A cross-sectional study design was used to assess the prevalence of HS in patients with AKN and in control participants matched by age, sex, and ethnicity. A total of 2677 participants with AKN and 13,190 control participants were studied. An increased prevalence of HS was observed in the AKN group compared to the control group (1.0% vs. 0.3%, respectively; OR, 3.6; 95% CI 2.2-5.8; P < 0.001), especially among those younger than 20 years (OR, 10.2; 95% CI 3.1-34.2; P < 0.001), and females (OR, 15.7; 95% CI 3.1-78.8; P < 0.001). After adjusting for confounding factors, the multivariate analysis demonstrated a persistent association of AKN with HS (adjusted OR, 3.6; 95% CI 2.1-5.9; P < 0.001). This study demonstrated a significant association between AKN and HS in an Israeli population. The threshold for diagnosis of HS among patients with AKN must be lowered in patients presenting with concerning symptoms. Further observational studies in other patient populations will help confirm this relationship.