Differences in omega-5-gliadin allergy: East versus West

BACKGROUND: Omega-5-gliadin (O5G) allergy, also known as wheat-dependent exercise-induced anaphylaxis, is commonly reported in the Western, but not Asian, populations. Although significant differences in O5G allergy presentation across different populations are likely but there have been no previous reports on this important topic. OBJECTIVE: To report on the prevalence and characteristics of O5G allergy in Hong Kong (HK) compared with the United Kingdom (UK). METHODS: O5G allergy patients attending Queen Mary Hospital (HK cohort), and Guy's and St Thomas' Hospital, London (UK cohort) were studied and compared. RESULTS: A total of 46 O5G allergy patients (16 HK; 30 UK) were studied. In the HK cohort, 55% of all patients previously labeled as “idiopathic anaphylaxis” were diagnosed with O5G allergy. Exercise was the most common cofactor in both cohorts, followed by alcohol and nonsteroidal anti-inflammatory drugs (NSAID). A higher proportion of the HK cohort reported NSAID as a cofactor (13% vs. 0%, p = 0.048). In the HK cohort, more patients presented with urticaria and cardiovascular manifestations (100% vs. 77%, p = 0.036; 100% vs. 70%, p = 0.015, respectively); the range of presentation was more diverse in the UK cohort. In HK fewer patients adhered to wheat avoidance (50% vs. 87%, p = 0.007) and more patients avoided cofactors only (44% vs. 10%, p = 0.008). CONCLUSION: O5G allergy appears relatively underdiagnosed in HK. Urticaria and cardiovascular manifestations are common; NSAID plays an important role as a cofactor and patients are less concordant with dietary avoidance measures than in the Western population.