Epinephrine could reduce hospitalizations in pediatric intensive care after a severe allergic reaction

Montreal, March 26, 2025 – During a severe allergic reaction (anaphylaxis), children who received epinephrine before arriving at the hospital are less likely to be hospitalized in intensive care, according to a recent study conducted at the Montreal Children’s Hospital (MCH).

Anaphylaxis is a severe allergic reaction that affects at least two organ systems and/or causes hypotension (low blood pressure). Between April 2011 and November 2023, researchers analyzed the cases of 3,158 patients who presented to the MCH Emergency Department with anaphylaxis. Of these, 44 percent had received epinephrine (for example with an EpiPen auto-injector) before arriving at the hospital and 56 percent had not.

The results showed a higher number of intensive care hospitalizations (1.6 percent) among patients who did not receive epinephrine before arriving at the hospital than among those who did (0.7 percent). No significant difference was noted in admissions to regular hospital wards, according to the study published in The Journal of Allergy and Clinical Immunology: In Practice.

“This confirms that the use of epinephrine before arrival at the hospital reduces significantly intensive care admissions for anaphylactic reactions. There is an urgent need for enhanced education and training for patients, parents and emergency medical services professionals to ensure that epinephrine is administered promptly,” emphasizes Dr. Moshe Ben-Shoshan, senior author of the study, Scientist in the Infectious Diseases and Immunity in Global Health Program at the Research Institute of the McGill University Health Centre, and pediatric allergy and immunology specialist at the MCH.

To determine the effect of this measure on hospitalizations, the researchers used propensity score matching – a method designed to estimate the impact of a treatment by accounting for variables that influence the likelihood of receiving it – eliminating confounding bias. Variables include the age at reaction, sex, known asthma, know food allergy, reaction at home and severity of reaction. This is the first study to use this propensity score matching to establish the association between the use of epinephrine before arrival at the hospital and hospital outcomes in anaphylaxis.

The study also analyzed the use of antihistamines prior to arrival at the hospital with propensity score matching, using the same covariables. While beneficial, the use of antihistamines alone has not shown a direct impact on hospital outcomes.

Some additional data:

• The median age was higher among patients who received epinephrine before arriving at the hospital (7.3 years, compared to 5 years among those who did not receive it).
• More patients who had received epinephrine before arriving at the hospital had a known food allergy (79 percent vs. 42.8 percent)
• These patients were more likely to have asthma (18.6 percent vs. 13.9 percent) and eczema (17.1 percent vs. 14.5 percent).
• Patients who received epinephrine before arriving at the hospital were less likely to have received antihistamines (41.6 percent vs. 45.8 percent) and more likely to have received corticosteroids (2.2 percent vs. 0.9 percent).

“Since the odds of receiving epinephrine before arriving at the hospital were significantly higher in patients with known food allergies, it is possible that these patients were better equipped to manage their condition,” Dr. Ben-Shoshan emphasizes.