The percentage of emergency department (ED) visits due to anaphylaxis more than doubled from 2011 to 2015 at one Canadian children’s hospital, according to a Research Letter to the Editor published in the Journal of Allergy and Clinical Immunology.
“Our results are limited to one pediatric center, but they suggest a worrisome increase in anaphylaxis rate that is consistent with the worldwide reported increase,” said Dr. Elana Hochstadter of the Hospital for Sick Children, University of Toronto, and her associates. The investigators analyzed longitudinal data in a national registry of anaphylaxis cases to track time trends for the disorder at their hospital. They identified 965 cases presenting to their ED during a 4-year period. The percentage of all ED visits accounted for by anaphylaxis rose from 0.20% to 0.41%. The overall volume of ED visits and the volume of specific ED diagnoses did not change during this interval.
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As in other studies of anaphylaxis around the world, food was the most common trigger in this series, responsible for 82% of cases. Peanut was the most common food allergen, accounting for 22% of cases. Most reactions were of moderate severity, and the percentages of mild, moderate, and severe reactions remained relatively stable throughout the study period. The presence of asthma was associated with increased severity of anaphylaxis (odds ratio, 2.3), as was the presence of eczema (OR, 2.1). Only half of the patients who had an epinephrine autoinjector used it before presenting to the ED, Dr. Hochstadter and her associates said (J Allergy Clin Immunol. 2016 doi: 10.1016/j.jaci.2016.02.016). The median age of the patients was 6 years.
The reason for this rapid increase is unknown, but it parallels that reported in studies of anaphylaxis throughout North America and Europe. “An important observation in our study is that administration of epinephrine before arrival in the ED is independently associated with a decreased likelihood of requiring multiple doses of epinephrine in the ED, suggesting that prompt epinephrine administration is beneficial,” they noted.
The Allergy, Genes, and Environment Network Centres of Excellence, Health Canada, and Sanofi funded the study. Dr. Hochstadter and her associates reported having no relevant disclosures.