Background: Allergenicity to heated egg yolks is known to be low in hen's egg allergy. However, there are few reports concerning the safety of an oral food challenge (OFC) with boiled egg yolks. This study aimed to determine the safety of a boiled egg yolk OFC and the clinical characteristics of patients who were OFC-positive.
Methods: We retrospectively examined the data of patients who underwent an OFC with one boiled egg yolk at Miyagi Children's Hospital between January 2013 and December 2020. Patients were included if they had a history of immediate symptoms due to hen's egg or positive specific IgE levels to egg yolk or egg white.
Results: Among 600 patients, 15.0% were positive for OFC, only one patient required an intramuscular adrenaline injection, and 70% of OFC-positive patients had gastrointestinal symptoms.
Conclusion: Boiled egg yolk OFC had a low symptom induction rate; however, when symptoms were induced, gastrointestinal symptoms were most commonly observed. Given the low risk of developing severe symptoms, we conclude that the likelihood of safely performing an OFC is high.
Keywords: allergens; egg hypersensitivity; egg yolk; food allergy; oral food challenge.