D2.320 - Safety and tolerability of stepwise oral food challenge using heated whole egg powder: a multicenter study

Oral food challenges (OFCs) are essential for diagnosing hen's egg (HE) allergy and determining safe consumption doses. However, accurate antigen quantification and standardization of preparation methods remain challenging. Heated whole egg powder, which allows for precise quantification, offers potential advantages, but its tolerability has not been evaluated across multiple institutions. We aimed to evaluate the tolerability and practicality of OFCs using heated whole egg powder through a multicenter questionnaire survey.

A questionnaire survey was conducted among physicians at medical institutions using heated whole egg powder from May 2024 to December 2025. The target population was children under 16 years of age with hen's egg allergy. The survey assessed the implementation status of OFCs using Tamakona 25, 250, and 750 (equivalent to 25, 250, and 750 mg of heated whole egg protein, respectively) and compared tolerability with conventional methods.

Responses were obtained from 38 institutions (17 hospitals, 21 clinics). A total of 237 OFCs were performed using heated whole egg powder, representing approximately 10% of the 2,369 total OFCs. The positive rates were 2% (1/50) for Tamakona 25, 13% (17/126) for Tamakona 250, and 10% (6/61) for Tamakona 750. Anaphylaxis occurred in 1 of 237 cases (0.4%). Compared with conventional methods, approximately 80% of physicians reported improvements in preparation time, convenience, and measurement accuracy. Safety was rated as "improved" by 40% and "equivalent" by 50% of respondents.

OFCs using heated whole egg powder demonstrated favorable tolerability, with superior convenience in preparation and measurement accuracy compared with conventional methods. This multicenter survey, which included both allergy specialty centers and general facilities without allergy specialists, suggests that heated whole egg powder may serve as a useful tool for standardizing HE OFCs and facilitating stepwise challenge protocols across diverse clinical settings.