Background: Despite careful avoidance measures, food allergic patients have a significant risk of anaphylactic episodes. Risk situations need to be identified for more efficient preventive measures.
Methods: Responders to an internet-based survey on the awareness of food anaphylaxis were invited to relate the circumstances of their most severe reaction following the diagnosis of IgE-mediated food allergy. Items of the questionnaire included the circumstances of the reaction and the treatment, as well as questions related to reactions occurring at specific categories of sites (i.e. home, schools, or restaurants).
Results: Fifty-one of the returned questionnaires (34.1%) corresponded to the study criteria. The median age of the subjects was 7 years (range 0.5-61), with 33/51 (64.7%) being less than 16 years of age. Reactions were reported to peanuts (24/51; 47.1%), milk (12/51; 23.5%), tree nuts (6/51; 11.8%), fish and shellfish (5/51; 9.8%), and others (3/51; 5.8%). Reactions occurred at home (13/51; 25.5%), in restaurants (9/51; 17.6%), at school or daycare or kindergarten (8/51; 15.7%), at a relative or friend's home (7/51; 13.7%), at sites of leisure activities (6/51; 11.8%), at work (3/51; 5.9%), in church or a hospital ward (2/51; 3.9% each), or in a food store (1/51; 2.0%). In severe reactions (37/51; 72.5%) epinephrine was administered in 28/37 (75.7%) of the responders. Finally, while most reactions happened after ingestion of the food (40/51; 78.4%), others were reported after skin contact exclusively (8/51; 16%), or after inhalation (3/51; 5.9%).
Conclusion: Food induced-anaphylaxis in patients aware of their allergy happens most often at sites considered as safe (i.e. home, schools, workplace, hospitals). Better strategies to avoid accidental reactions include clear labelling of forbidden foods and increased information at all levels. These might dramatically reduce the risk of food-induced anaphylaxis in food allergy sufferers.