D2.06 - Clinical Characteristics of Reactions to Oral Food Challenges with Egg- and Milk-Based Muffins in Children

Oral food challenges (OFCs) are essential for the evaluation of hen’s egg and cow’s milk allergies. Baked egg-based muffins (BEs) and milk-based muffins (BMs), as well as scrambled eggs and fresh milk, are commonly used in OFCs because of their reduced allergenicity. However, delayed-onset reactions to BEs and BMs have raised safety concerns. In addition, the clinical characteristics of BE- and BM-OFC-induced reactions remain unclear.

We retrospectively analysed the OFCs performed between April 2021 and September 2025 in children with immediate hen’s egg or cow’s milk allergies at our institution. The BEs were prepared from hen’s eggs and rice flour, whereas the BMs were prepared from cow’s milk and rice flour. Only patients who were OFC-positive with objective allergic symptoms were included in this study. Organ-specific symptoms, time from final ingestion to symptom onset, and adrenaline administration rates were evaluated and compared between the BE/BM and scrambled-egg or fresh-milk challenges.

We analysed 227 OFC-positive cases with hen’s egg allergy (median age: 5.8 years), including 182 challenges with scrambled eggs and 45 with BEs. In addition, 99 OFC-positive cases of cow’s milk allergy (median age: 5.8 years) were analysed, including 71 and 28 OFCs with fresh milk and BMs, respectively. Skin symptoms were observed significantly more frequently during OFCs with scrambled egg and fresh milk than during those with baked egg or baked milk (p < 0.05). In contrast, gastrointestinal symptoms occurred significantly more often during OFCs with baked egg and baked milk than during OFCs with scrambled egg and fresh milk (p < 0.001 and p < 0.05, respectively). There were no significant differences in the time from final ingestion to symptom onset or in the rate of adrenaline administration.

BE- and BM-OFC-induced reactions were not associated with increased severity or delayed onset compared with scrambled-egg or fresh-milk challenges. However, because skin symptoms are less frequent, gastrointestinal and other organ-specific symptoms must be considered. Careful and sufficiently prolonged observation is essential when performing BE and BM OFCs to ensure patient safety.