Hidradenitis suppurativa and inflammatory bowel disease in a nested case-control study

Background: Association between Hidradenitis Suppurativa (HS) and Inflammatory Bowel Disease (IBD) has been suggested.Aims: To assess characteristics of HS and IBD in patients with or without concomitant IBD.Methods: In a prospective, nested case-control study, each IBD patient with concomitant HS (Case) was retrospectively matched with 4 patients with HS and no IBD (Controls) for gender and age ( +/- 5 years).HS was classified according to the Hurley score and the International Hidradenitis Suppurativa Severity Score System (IHS4). Data were expressed as mean (Standard Deviation). Statistical analysis included Student-t Test or Mann-Whitney Test, chi 2 test, univariate and multivariate logistic regression. Results: The study population included 125 patients with HS: 25 with IBD, 100 matched Controls with no IBD. IBD group included 19 (76%) Crohn's disease and 6 (24%) Ulcerative Colitis patients. Obesity, familial HS and perianal HS were less frequent in Cases than in Controls (1[4%] vs 25(25%]; p = 0.02; 1[4%] vs 21(21%]; p = 0.04; 1[4%] vs 31(31%]; p = 0.005, respectively).HS was less severe in Cases when assessed by the IHS4 (5.9 +/- 4 vs 9 +/- 6.7; p = 0.04).Complete drug-induced response for HS was more frequent in IBD (13[53%] vs28 (28%]; p = 0.04).Conclusion: Clinical characteristics of HS and of patients differed between Cases and Controls. Present findings suggest the need to appropriately search and assess skin lesions compatible with HS in IBD.(c) 2022 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.