Background: In Europe, Omalizumab (anti-IgE) is indicated for the treatment of moderate/severe asthma, but not for IgE-mediated food allergy (FA). Objective: We prospectively assessed the impact of Omalizumab for efficacy, safety, and quality of life (FA-QoL) in patients with moderate/severe asthma and history of anaphylaxis to peanut, tree nuts, fish, egg, milk, and/or wheat. Methods: Food-allergic children (6-18yrs) with moderate/severe asthma underwent oral food challenges (OFCs) to establish the threshold of reaction to the culprit food(s) at baseline (T0) and at four-month intervals (T1, T2, T3) during their first year of treatment with Omalizumab. We recorded the number and severity of food-allergic reactions, Asthma Control Test (ACT), FA-QoL, and total IgE. Results: In 65 patients allergic to 107 foods, the No Observed Adverse Events Level (NOAEL) at T1 increased: 243- and 488-fold for raw and baked milk, respectively; 172 and 134-fold for raw and baked egg; 245-fold for hazelnut; 55-fold for peanut; 31-fold for wheat, and 10-fold for fish. Full tolerance was achieved in 66.4% of OFCs at T1, 58.3% at T2, and 75% at T3. Ninety-five foods were liberalized ad libitum in the diet of 55 patients; the remaining 12 were introduced by 10 patients at least in traces. Throughout the study, 40/65 children got a free diet. ACT increased from 17 (Q1-Q3:15-17) to 23.6 (Q1-Q3:23-25). The FA-QoL score in children ≤ 12 years decreased from 4.63±0.74 to 2.02±1.13, in adolescents from 4.68±0.92 to 1.90±1.50. Conclusions: Omalizumab allows safe reintroduction of allergenic foods. Trial registration number: ClinicalTrials.gov, NCT06316414

Background. The use of eliciting doses (EDs) for food allergens is necessary to inform individual dietary advice and food allergen risk-management. The Eliciting Dose 01 (ED01) for milk and egg, calculated from populations of allergic subjects undergoing diagnostic Oral Food Challenges (OFCs), are 0.2 mg total protein. The respective Eliciting Dose 05 (ED05) are 2.4 mg for milk and 2.3 mg for egg. As about 70% children allergic to such foods may tolerate them when baked, we sought to verify the EDs of that subpopulation of milk and egg-allergic children. Methods. We retrospectively assessed consecutive diagnostic OFC for fresh milk and egg between January 2018 and December 2020 in a population of baked food-tolerant children. Results. Among 288 children (median age 56 - IQR 36-92.5 months, 67.1% male) included, 87 (30.2%) returned positive OFC results, 38 with milk and 49 with egg. The most conservative ED01 were 0.3 mg total protein (IQR 0.03-2.9) for milk and 14.4 mg total protein (IQR 3.6-56.9) for egg. The respective ED05 were 4.2 (IQR 0.9-19.6) mg for milk and 87.7 (IQR 43-179) mg for egg. Such thresholds are respectively 1.5 (milk ED01), 1.75 (milk ED05), 72 (egg ED01), and 38.35 (egg ED05) times higher than the currently used thresholds. Conclusions The subpopulation of children allergic to milk and egg, but tolerant to baked proteins, displays higher reactivity thresholds than the general population of children allergic to milk and egg. Their risk stratification, in both individual and population terms, should consider this difference. In baked milk-tolerant children, milk causes reactions at lower doses than egg in our group of egg-tolerant children. This could be associated with the relative harmlessness of egg compared to milk in the determinism of fatal anaphylactic reactions in children