Published Online: July 29, 2013
Anaphylaxis is a substantial health problem and it is reported to be increasing. However, the societal burden in Canada remains largely undefined. Although a few studies in the US, Europe, and Australia have examined anaphylaxis, these are all limited by their reliance on review of medical charts. In a recent publication, in The Journal of Allergy & Clinical Immunology (JACI), Ben-Shoshan et al, aimed to overcome these methodological limitations and provide Canadian data on the rate, triggers, and management of anaphylaxis by prospectively recruiting cases presenting to the emergency department of the Montreal Children’s Hospital, Montreal, Canada. In addition, cases not recruited at the time of presentation were identified through chart review of all cases with diagnostic codes that are related to either anaphylaxis or an allergic reaction.
The researchers found that among 81,677 emergency department visits over one year, 168 [80 of whom (47.6%) were recruited prospectively] presented with anaphylaxis, i.e. 0.21% (95% CI, 0.18%, 0.24%). Food was responsible for 84.5% of reactions with peanut/tree-nut accounting for almost 50% of food-induced reactions. Half of milk and peanut induced anaphylaxis cases were attributed to inadvertent exposure to the known allergen. Among those with moderate and mild reactions, 23.1% and 35.9% respectively did not receive epinephrine either outside or inside the emergency department. Of those with moderate/severe reactions, 18 had an auto-injector with them at the time of reaction, but only 12 used it. Reaction severity was associated with peanut or venom exposure and asthma.
This is the first study that collects data on anaphylaxis at the time reaction occurs and follows individuals over a defined period of time. Anaphylaxis rates in this Canadian study are comparable to rates estimated in the US but exceed rates in European and Australian studies. Inadvertent exposure is common and auto-injectors are relatively underused.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.