Risk Factors for Hidradenitis Suppurativa in Patients with Inflammatory Bowel Disease.

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder characterized by recurrent nodules, abscesses, and sinus tracts that can be debilitating and significantly impair quality of life. Small studies and case reports have suggested a possible association between HS and inflammatory bowel disease (IBD).

AIMS: We performed a case-control study to further characterize IBD patients with HS in terms of smoking status, BMI, sites affected by HS, IBD type and features, and IBD medication history.

METHODS: A total of 38 patients with HS and IBD were identified and matched on age, gender, and IBD type to 136 controls with IBD but not HS. Clinical characteristics of interest were obtained through extensive review of the electronic health record.

RESULTS: Among patients with HS and IBD, the most common sites affected by HS were the inguinal, perianal, and axillary regions. Relative to patients with IBD alone, patients with HS and IBD were nearly six times more likely to be current smokers (p < 0.01) and nearly 11 times more likely to be obese (p < 0.01). Patients with HS and Crohn's were significantly more likely to have ileocolonic and perianal disease than patients with CD only (OR 8.31, 95% CI 2.90-23.80 and OR 2.85, 95% CI 1.19-6.81, respectively; p < 0.01 for both).

CONCLUSIONS: Relative to patients with IBD who do not develop HS, patients with IBD and HS are more likely to be overweight or obese, to be former or current smokers, and to have ileocolonic and/or perianal disease.