Hidradenitis Suppurativa in Patients With Inflammatory Bowel Disease: A Population-Based Cohort Study in Olmsted County, Minnesota

Background & Aims: Patients with inflammatory bowel disease (IBD) may be at higher risk for hidradenitis suppurativa (HS). We studied the risk and clinical characteristics of HS in a population-based cohort of patients with IBD. Methods: We identified all cases of HS (confirmed by biopsy and/or dermatologic evaluation) in a population-based inception cohort of Olmsted County, Minnesota, residents diagnosed with IBD between 1970 and 2004 and followed up through August 2013. We estimated the incidence rate ratio of HS in patients with IBD compared with the general population, and described the clinical characteristics, risk factors, and management of HS. Results: In 679 IBD patients followed up over a median of 19.8 years, we identified 8 patients with HS (mean age, 44.4 ± 8.3 y; 7 women; 6 obese). Compared with the general population, the incidence rate ratio of HS in IBD was 8.9 (95% confidence interval, 3.6-17.5). The 10- and 30-year cumulative incidence of HS was 0.85% and 1.55%, respectively. Five patients had Crohn's disease, 4 of whom had perianal disease; of 3 patients with ulcerative colitis, 2 had undergone ileal pouch-anal anastomosis. Axillae, groin, and thighs were the most common sites of involvement. Six patients had Hurley stage 2 disease (recurrent abscesses with sinus tracts and scarring, involving widely separated areas), and required a combination of antibiotics and surgery; none of the patients were treated with anti-tumor necrosis factor-α agents. Conclusions: In this population-based study, patients with IBD were approximately 9 times more likely to develop HS than the general population, with a female predisposition.