Tree nut-induced anaphylaxis in Canadian emergency departments: Rate, clinical characteristics, and management

Background: Data are sparse regarding tree nut-induced anaphylaxis (TNA). Objective: To characterize rate, clinical characteristics, and management of TNA in children (0-17 years old) across Canada and evaluate factors associated with severe reactions and epinephrine use.Methods: Between April 2011 and May 2020, data were collected on children presenting to 5 emergency depart-ments in Canada. Multivariate logistic analysis was used to evaluate factors associated with severe reactions (stridor, cyanosis, circulatory collapse, or hypoxia) and epinephrine use.Results: Among 3096 cases of anaphylaxis, 540 (17%) were induced by tree nut. The median age was 5.2 (inter -quartile range, 2.5-9.5) years and 65.4% were of male sex. Among all reactions, 7.0% were severe. The major tree nuts accounting for anaphylaxis were cashew (32.8%), hazelnut (20.0%), and walnut (11.5%). Cashew-induced anaphylaxis was more common in British Columbia (14.0% difference [95% confidence interval (CI), 1.6-27.6]) vs Ontario and Quebec, whereas pistachio-induced anaphylaxis was more common in Ontario and Quebec (6.3% dif-ference [95% CI, 0.5-12.2]). Prehospital and emergency department intramuscular epinephrine administration was documented in only 35.2% and 52.4% of cases, respectively. Severe reactions were more likely among of male sex (adjusted odds ratio [aOR], 1.05 [95% CI, 1.01-1.10]), older children (aOR, 1.00 [95% CI, 1.00-1.01]), and in reactions triggered by macadamia (aOR, 1.27 [95% CI, 1.03-1.57]).Conclusion: Different TNA patterns in Canada may be because of differences in lifestyle (higher prevalence of Asian ethnicity in British Columbia vs Arabic ethnicity in Ontario and Quebec). Intramuscular epinephrine under-utilization urges for epinephrine autoinjector stocking in schools and restaurants, patient education, and consis-tent policies across Canada.(c) 2022 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.