ABSTRACT
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.
Subject(s)
Humans , Anaphylaxis , Asian People , Cohort Studies , United Kingdom , Hong Kong , Hypersensitivity , Prevalence , Triticum , UrticariaABSTRACT
There are geographical, regional, and ethnic differences in the phenotypes and endotypes of patients with drug hypersensitivity reactions (DHRs) in different parts of the world. In Asia, aspects of drug hypersensitivity of regional importance include IgE-mediated allergies and T-cell-mediated reactions, including severe cutaneous adverse reactions (SCARs), to beta-lactam antibiotics, antituberculous drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) and radiocontrast agents. Delabeling of low-risk penicillin allergy using direct oral provocation tests without skin tests have been found to be useful where the drug plausibility of the index reaction is low. Genetic risk associations of relevance to Asia include human leucocyte antigen (HLA)-B*1502 with carbamazepine SCAR, and HLA-B*5801 with allopurinol SCAR in some Asian ethnic groups. There remains a lack of safe and accurate diagnostic tests for antituberculous drug allergy, other than relatively high-risk desensitization regimes to first-line antituberculous therapy. NSAID hypersensitivity is common among both adults and children in Asia, with regional differences in phenotype especially among adults. Low dose aspirin desensitization is an important therapeutic modality in individuals with cross-reactive NSAID hypersensitivity and coronary artery disease following percutaneous coronary intervention. Skin testing allows patients with radiocontrast media hypersensitivity to confirm the suspected agent and test for alternatives, especially when contrasted scans are needed for future monitoring of disease relapse or progression, especially cancers.