Sensitization to α-gal and omega-5-gliadin in patients with chronic urticaria: clinical implications and need for targeted testing

Introduction: Chronic urticaria (CU) is defined as the presence of recurring hives and/or angioedema lasting more than 6 weeks. The precise impact of food allergies, particularly to galactose-alpha-1,3-galactose (alpha-gal) and omega5-gliadin (O5G), on the development of CU is not well established. Aim: The study examines the frequency of sensitisation to these allergens and their clinical significance in individuals with CU. Material and methods: We recruited 100 adults newly diagnosed with CU to evaluate the presence of specific immunoglobulin E antibodies and allergies to alpha-gal and O5G. The patients were categorised into three groups based on their specific IgE levels: those sensitised to alpha-gal, those sensitised to O5G, and those not sensitised to either. Demographic, clinical, and laboratory variables were compared across the groups. Results: The findings indicated that 5% of the cohort was sensitised to alpha-gal, and 4% showed sensitivity to O5G, while only 4% of patients had a convincing history of food allergy (two to red meat and two to wheat). The sensitised groups exhibited the greatest levels of total IgE, and had a higher proportion of males. The alpha-gal group showed higher levels of specific IgE to Ascaris lumbricoides than the group without sensitisation. The groups had similar features in all other assessed aspects. Conclusions: Our CU cohort's sensitivity and convincing food allergy to alpha-gal and O5G were comparatively modest. While routine screening may not be essential, focused testing of individuals with severe or uncommon symptoms might enhance the accuracy of diagnosis and treatment.