TOPLINE

Allergic reactions requiring epinephrine were uncommon among preschool children undergoing oral immunotherapy (OIT) for food allergies; however, certain patient characteristics — including higher baseline food allergen-specific immunoglobulin E (IgE) levels and treatment for multiple foods — were associated with increased risk.

METHODOLOGY

• Researchers conducted a prospective, multicenter study using a Canadian registry to describe reactions requiring epinephrine among preschool children receiving OIT for food allergy.
• The study included 1868 children younger than 72 months who received OIT between July 2017 and November 2024 at allergy centers across Canada. The treatment followed published protocols and had two phases: a buildup phase, in which doses were gradually increased, and a maintenance phase.
• The researchers compared children who received epinephrine during OIT with those who did not, based on food-specific IgE levels at baseline, other allergic conditions, and whether OIT was given for one food or multiple foods.
• The reactions receiving epinephrine were described, including timing, treatment phase (buildup or maintenance), setting (clinic or home), and cofactors — defined as conditions that can trigger a reaction at a lower dose — such as concurrent febrile illness and dosing on an empty stomach.

TAKEAWAY

• Overall, 97 of 1868 children (5.2%) required epinephrine on 128 occasions during OIT. The median age at which these events occurred was 45 months.
• Children who received epinephrine had higher baseline serum IgE levels to their most severe treated food allergen, more frequent atopic comorbidities, and more severe pre-OIT reactions to the treated food and were more likely to undergo multi-food OIT than those who did not (P < .05 for all).
• The reactions requiring epinephrine occurred more often in the buildup phase of OIT than in the maintenance phase (58.6% vs 28.1%). A significant number of reactions (35.1%) occurred with daily doses taken at home, soon after dose administration (median, 40 minutes).
• Concurrent febrile illness was the leading cofactor (21.0%), followed by dosing on the empty stomach (6.7%); the majority of reactions (64.8%) had no cofactor identified. Most epinephrine-treated reactions (63.3%) were classified as grade 1 or 2 under the 2024 World Allergy Organization criteria, although six patients (5.0%) experienced severe grade 4 reactions.

IN PRACTICE

"Our study also supports the safety of preschool OIT, as the vast majority of reactions receiving epinephrine were mild (grade 1 or 2) reactions, and severe (grade 4) reactions during OIT were rare. The first few dose escalations during the early build-up phase (1-20 mg protein) represent the highest risk period, and reactions were more likely to occur during daily dosing at home," the authors wrote.

SOURCE

Min Jung Kim, MD, with Western University in London, Ontario, and Vicky Le Blanc, MD, with the University of British Columbia in Vancouver, both in Canada, were the corresponding authors of the study, which was published online on October 09, 2026, in The Journal of Allergy and Clinical Immunology: In Practice.

LIMITATIONS

The study was limited by the relatively small epinephrine group and the low number of grade 4 reactions, which reduced the ability to identify combinations of characteristics and cofactors that might predict severe reactions.

DISCLOSURES

The study was supported by the BC Children's Hospital Foundation and the BC Children's Hospital Research Institute. Several authors reported receiving honoraria and serving on advisory boards for various sources. One author declared working for the Public Health Agency of Canada.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.