Recognizing and managing food- dependent exercise-induced anaphylaxis

The role of these co-factors in promoting anaphylaxis in food-dependent exerciseinduced anaphylaxis is not entirely clear, but several models have been proposed. One theory argues that blood is diverted from the gut during exercise, causing relative ischaemia which increases gut permeability and thus the delivery of food allergens into the circulation (Matsuo et al, 2005). Palosuo et al (2003) proposed that exercise activates the gut enzyme tissue transglutaminase which aggregates with omega-5-gliadin to form a high molecular weight complex that binds to immunoglobulin E with high affinity. Finally, exercise-associated changes in blood pH and osmolality could directly reduce the threshold for mast cell and basophil degranulation (Cooper et al, 2007). The diagnosis of food-dependent exerciseinduced anaphylaxis is largely clinical, based on the recognition of systemic anaphylaxis following exposure to a particular food allergen in association with specific cofactors. It is important to know that food and exercise are independently tolerated. The clinical features of anaphylaxis including urticaria, angioedema, breathing difficulties and collapse each have a wide differential diagnosis, and a diagnosis of ‘allergic reaction’ made in the emergency department is frequently revised in clinic. For example, urticaria may be spontaneous (often having an autoimmune aetiology), physical (resulting from mast cell degranulation in response to physical stimuli), drug-induced in a non-specific manner or associated with