A history of asthma is associated with susceptibility to hidradenitis suppurativa: a population-based longitudinal study

The association of hidradenitis suppurativa (HS) and asthma remains to be investigated. To assess the bidirectional association between HS and asthma. A population-based study was conducted to compare HS patients ( n = 6779) with age-, sex-, and ethnicity-matched control subjects ( n = 33,259) with regard to the incidence of new onset and the prevalence of preexisting asthma. Adjusted hazard ratios (HRs) and adjusted odds ratios (ORs) were calculated. The prevalence of preexisting asthma was higher in patients with HS relative to controls (9.6% vs. 6.9%, respectively; P < 0.001). The odds of HS were 1.4-fold greater in patients with a history of asthma (fully adjusted OR 1.41; 95% CI 1.27–1.55; P < 0.001). The incidence rate of new-onset asthma was estimated at 9.0 (95% CI 6.3–12.7) and 6.2 (95% CI 5.1–7.5) cases per 10,000 person-years among patients with HS and controls, respectively. The risk of asthma was not statistically different in patients with HS and controls (fully adjusted HR 1.53; 95% CI 0.98–2.38; P = 0.062). Relative to other patients with HS, those with HS and comorbid asthma were younger at the onset of HS (30.7 [14.7] vs. 33.3 [15.1], respectively; P < 0.001) and had a comparable risk of all-cause mortality (adjusted HR 0.86; 95% CI 0.44–1.68; P = 0.660). A history of asthma confers susceptibility to subsequent development of HS. This observation is of importance for clinicians managing both patients with HS and asthma. Further research is warranted to elucidate the pathomechanism underlying this finding.