ALLERGY IN OROFACIAL GRANULOMATOSIS AND INFLAMMATORY BOWEL DISEASE

Introduction Orofacial granulomatosis (OFG), including oral Crohn9s disease (CD) is a chronic inflammatory condition presenting characteristically with lip swelling but also affecting a number of other sites in the oral cavity. Bouts of acute swelling and frequently reported atopy suggest an allergic component. There is evidence for dietary triggers with objective improvement on a cinnamon and benzoate-free diet.1 The Oral Allergy Syndrome (OAS) is a well recognised condition with a clear immunological pathogenesis.2 There are similarities between OAS and OFG in terms of symptoms, triggers and treatment regimes. The role of allergy in inflammatory bowel disease (IBD) remains unclear with conflicting data in the literature. Methods We performed skin prick tests to common allergens in a cohort of 88 patients with biopsy proven OFG between August 2007 and July 2009. We measured Specific serum IgE levels to relevant allergens and total serum IgE levels. The prevalence of OAS in patients with OFG was also determined. For comparison, a group of 121 consecutive patients with a confirmed diagnosis of IBD without oral involvement were also studied. Results The incidence of clinical allergy of 82% in the OFG cohort was considerably higher than the 4–20% incidence reported in the general population. OAS incidence was 28%, also significantly higher than population estimates. OFG patients with disease onset below 30 years and no concomitant CD had a significantly higher incidence of allergy (95%) and OAS (38%). ImmunCAP and total serum IgE levels also confirmed increased allergy. Allergy in CD (39%) was higher than the general population, especially in the colonic (43%) and ileocolonic (52%) compared to the ileal group (24%). Allergy in Ulcerative colitis was comparable to population estimates (18%). Conclusion Patients with OFG have an astonishingly high incidence of allergy. A large proportion of patients have OAS. A novel subepithelial dendritic B cell population demonstrating class switching to IgE, described in oral biopsies from patients with OFG by our group, could provide the link between dietary antigens, chronic oral inflammation and symptoms of hypersensitivity.3 The comparative significance of the differences in allergy in the different IBD groups remains unclear.