Severe Anaphylactic Reactions to Home Doses of Oral Immunotherapy for Food Allergy.

Abstract

Severe anaphylactic reactions to home-doses may occur during food allergy oral immunotherapy (OIT). To study the rate and risk factors for such reactions. All patients aged >3.5 years who completed OIT in a single center, between April-2010 and January-2020, were studied. All home epinephrine-treated reactions (HETRs) were identified. High-grade HETRs (HG-HETRs) were defined as HETR involving respiratory (SpO2 ≤94%), cardiovascular (low blood pressure), or CNS (loss of consciousness) impairment. The rate and risk factors for HG-HETRs were investigated. A total of 1637 OIT treatments were studied: milk, 880; peanut, 346; tree-nuts, 221; sesame, 115; and egg, 75. Of 390 identified HETRs, 30 HG-HETRs occurred during 27 treatments (1.65% of all treatments). Nearly all (26/30) were during milk OIT in patients with HDM-sensitization and asthma (26/30 each). Of the 30 HG-HETRs, 21 recovered with 1-2 epinephrine treatments, but 9 cases (0.55% of all treatments) did not respond to a second dose of epinephrine and were deemed refractory anaphylaxis. Three patients required ICU admission, and 3 received epinephrine drip but none required ventilatory support. Risk factors for HG-HETRs included milk-OIT (p=0.031), asthma (p=0.02) and house dust mite (HDM) sensitization (p=0.02). No specific triggers for HG-HETR were identified. Of patients with HG-HETRs, 25.9% were fully desensitized, including the 4 non-milk treated patients, 22.2% were partially desensitized and 51.9% failed. HG-HETRs and particularly refractory anaphylactic reactions to home OIT doses are uncommon. While milk OIT, asthma and HDM sensitization are the main risk factors for such reactions, identification of patients at risk is challenging.