Safety and feasibility of heated egg yolk challenge for children with egg allergies
Egg yolk is a binder used to make many foods 8. Although most patients allergic to raw eggs can consume heated whole eggs 9, patients reactive to heated whole egg, including various threshold doses 10, are generally instructed to completely eliminate eggs from their diets 6. Egg white is the major allergen in hen's egg 8; egg yolks are less allergenic than egg whites 11. Egg whites and yolks have shown cross‐reactivity in vitro12; nevertheless, clinical cross‐reactivity is unknown.
The oral food challenge (OFC) test is the gold standard for diagnosing and confirming acquired tolerance to food allergies 5. Although there are some reports about hen's egg OFCs 15, there is limited knowledge about egg yolk OFCs 18, and no reports regarding heated egg yolk OFC.
The quality of life (QOL) of patients with egg allergies and their guardians is poor regarding meal selection, risk of reaction, and prognosis 19. If small amounts of egg (e.g., in breads, cookies, and seasonings) could be ingested, QOL may improve 21. Moreover, if accidental exposure to small amounts of egg products caused no symptoms, fear of severe symptoms upon accidental ingestion would decrease. The aim of this study was to clarify whether pediatric patients who reacted to heated whole egg could safely consume heated egg yolk.