Hidradenitis suppurativa and pemphigus: a cross-sectional study.

A recent study of comorbidities in hospitalized pemphigus patients in the United States has demonstrated a significant association of hidradenitis suppurativa (HS) and pemphigus, but this association has not been firmly established in other populations. A retrospective, cross-sectional study was undertaken to determine the prevalence of HS in patients with pemphigus and compare with control subjects. Regression analysis was performed to obtain ORs, and 95% CIs, to evaluate the prevalence between pemphigus patients and controls matched by age, sex, and ethnicity. Among the patients included in the study, 1985 patients had pemphigus and 9874 were control subjects. The average age of presentation of pemphigus was 72.1 ± 18.5 and the group was comprised of 59.8% females. Overall, the pemphigus group had lower rates of smoking (25.7% vs. 27.9%; P = 0.045). The prevalence of HS was greater in patients with pemphigus than in control subjects (OR 4.98; 95% CI 1.01-24.69; P < 0.001), with an even more prominent association among patients who have been prescribed "pemphigus-related treatments" (OR 6.30; 95% CI 1.27-31.22; P < 0.001). The study detected a significant association between HS and pemphigus in an Israeli population. Future prospective studies are needed to establish a temporal order of appearance and the mechanistic relationship between these entities.