S0862 Increased Prevalence of Dermatitis Herpetiformis Among Patients With IBD Without Concomitant Celiac Disease: Results From a Population-Based Study

Abstract

INTRODUCTION: Dermatitis herpetiformis (DH) is an autoimmune eruption of pruritic inflammatory papules and vesicles that occur in a grouped arrangement on different parts of the body. It is characterized by granular deposits of immunoglobulin A (IgA) within the dermal papillae on immunofluorescence. Previous case studies (Alonso-Llamazares et al) and case reports have described an association between DH and ulcerative colitis, possibly arising due to an increased permeability of intestinal mucosal barrier in inflammatory bowel disease (IBD) that allows antigen to circulate in the blood and triggering IgA antibodies. Using a large database, we sought to describe the epidemiology and risk of DH in IBD patients. METHODS: We used a commercial database (Explorys Inc, Cleveland, OH), an aggregate of Electronic Health Record data from 26 US healthcare systems. We identified a cohort of patients with IBD, celiac disease and a diagnosis of DH between June 2015 and 2020. Patients were identified based on a Systemized Nomenclature of Medicine Clinical Terms. We calculated the prevalence of DH in patients with IBD, with celiac, general population, and in individuals with neither IBD nor celiac which served as controls. RESULTS: Out of the 39,212,680 patients active from 2015 to 2020, we identified a total of 5,240 patients with DH (0.013%), 280,460 patients with IBD (0.71%), and 115,020 patients with celiac disease (0.29%). Among those with DH, there were 1290 patients diagnosed with celiac disease (without IBD), 120 patients with IBD (without CD), 60 patients with both celiac and IBD, and 3770 patients with neither celiac nor IBD (control group). The prevalence of DH was 1.12% in celiac disease (without IBD) and 0.043% in IBD (without CD). The prevalence of DH among those without celiac nor IBD (in the control group) was 0.0096%. The risk of DH was higher in celiac [OR 116.6 (109.4–124.2)] and in IBD [OR 4.41 (3.68–5.29)] compared to individuals with neither IBD nor celiac. In the cohort with IBD, risk of DH was higher in females compared to males [OR 3.06 (1.77–5.30)], in elderly patients compared to adults aged 18–65 [4.0 (2.34–6.84)], and in Caucasians compared to non-Caucasians (OR 25.0 [12.7–49.3]). CONCLUSION: Using a large population database, we described the epidemiology and risk of DH in IBD patients. We found that the risk of DH is increased in patients with IBD, consistent with prior case series. Further studies are needed to confirm this association and elucidate the mechanism behind this association.Table 1.: Odd’s ratio comparing the prevalence of dermatitis herpetiformis in celiac disease and in IBD to patients with DH without celiac or IBDTable 2.: Gender-, Age- and Race-Based Prevalence of dermatitis herpetiformis in individuals with IBD in the United States between 2015 and 2020