Self-reported accidental allergic reactions among patients with challenge-verified food allergy

Abstract

Background: Food allergy affects up to 6% of the population and emergency department visits due to accidental food-allergic reactions are increasing. This study evaluated accidental allergic reactions outside the hospital and the number of hospitalizations in food allergic patients as well as the pattern before and after the diagnosis of food allergy by oral food challenge (OFC).

Methods: An electronic questionnaire concerning accidental allergic reactions was sent to 785 patients with challenge verified peanuts, hazelnuts, cow's milk and/or hen's egg allergies at the Allergy Centre, Odense University Hospital, Denmark.

Results: In total, 51% (402/785) responded. Among the 357 who reported at least one accidental allergic reaction, 51.5% (184/357) reported a total of six or less reactions, whereas 22.4% (80/357) had experienced a total of ≥21 reactions. Skin symptoms were commonly reported by children/adolescents (n = 277), whereas symptoms from all other organ systems were more frequently reported by adults (n = 80). In total, 61.6% (220/357) experienced at least one accidental allergic reaction, requiring immediate medical attention, which decreased from 77.3% (170/220) before to 55% (121/220) after establishment of the food allergy diagnosis by OFC. A concomitant proportional increase in the number of hospitalizations was identified (63.5% (108/170) to 72.7% (88/121)).

Limitations: We had no exact data on the timing of the accidental allergic reactions for the individual allergens.

Conclusion: Accidental food-allergic reactions are common and often severe. After the diagnostic OFC, the number of patients with reactions decreased, and the proportion of hospitalizations increased, indicating improved disease and healthcare management.

Keywords: accidental allergic reaction; allergic reactions; anaphylaxis; food allergy; oral food challenge.

FIGURE 1

Flow diagram of patients with allergy to peanuts, hazelnuts, cow's milk, and hen's egg diagnosed by oral food challenge between 2001 and 2015 at the Department of Dermatology and Allergy Centre, Odense University Hospital, Denmark. OFC, oral food challenge. ¹Severe allergic reactions were defined as accidental allergic reactions to peanuts, hazelnuts, cow's milk or hen's egg outside the hospital settings that required immediate medical attention.

FIGURE 2

The cumulative number of challenge‐verified allergic patients (n = 357) who have experienced accidental allergic reactions outside the hospital setting to the culprit allergens peanuts, hazelnuts, cow's milk and/or hen's egg. Each column represents the cumulative number of patients (given on the y‐axis) who reported experiencing a total number of accidental allergic reactions corresponding to or higher than the given number on the x‐axis. Severe allergic reactions were defined as accidental reactions to any peanuts, hazelnuts, cow's milk, or hen's egg outside the hospital setting requiring immediate medical attention (e.g., attendance to the acute ward). Among all the patients with at least one accidental allergic reaction outside a hospital setting, 137 (38.4%) had not experienced a severe reaction requiring immediate medical attention to peanuts, hazelnuts, cow's milk, or hen's egg. Patients with 1–2 severe allergic reactions were subsequently presented in the non‐severe column if the number of non‐severe accidental allergic reactions was higher than that of severe reactions.

FIGURE 3

Symptoms listed by organ system comparing children and adolescents (≤17 years) versus adults (≥18 years) among all patients (n = 357) who specified the symptomatology experienced during the accidental allergic reactions to peanuts, hazelnuts, cow's milk or hen's egg outside a hospital setting. If the patient experienced symptoms during multiple accidental allergic reactions to peanuts, hazelnuts, cow's milk, or hen's eggs, the reaction with the highest Sampson's severity score was presented. *χ ²‐test p‐value <0.05, comparing ≤17 years versus ≥ 18 years. **χ ²‐test p‐value <0.001, comparing ≤17 years versus ≥ 18 years.

FIGURE 4

Distributions of all patients (n = 220) with at least one accidental allergic reaction to any of the four culprit allergens outside a hospital settings, requiring immediate medical attention, before and after diagnosis of allergy to peanuts, hazelnuts, cow's milk, and hen's egg by oral food challenge.