D1.185 - One-day oral challenge test in low risk nut allergic children

Nuts are one of the main causes of food anaphylaxis. As they are hidden allergens,avoidance is difficult affecting significantly patient's quality of life.Our aim was to establish a one-day oral challenge test (OCT) to a mix of nuts in low-risknut allergic patients.

We included 21 patients with allergy to one or more nuts (May-2024 to Feb-2025). Inall cases, skin tests (prick and prick by prick) to nuts, and specific-IgE (SiemensImmulite®) against all different nut allergens were performed. The positive cut-offvalue was ≥0.1 kU/L.The nut-mix OCT was performed with those with negative results (prick tests andspecific-IgE) and unknown tolerance.

Out of 21 patients, 52.3 % were female, mean age 10.3 y.o (age-range 5-17). The mostfrequent nut inducing allergy was walnut(52%) followed by peanut (28.5%), hazelnutand cashew-pistacchio (23%) and pine nut (5%). Concerning symptoms, 52.5%presented urticaria/angioedema, 38% anaphylaxis and 9.5% SAO.Storage proteins were the most frequently sensitization pattern in walnut (38%)peanut(14.3%), hazelnut and cashew-pistacchio(100%).

Regarding OCT to the mix, 16 cases received ≥ 3 different nuts and in 5,only two. Themost frequently nut administered was almond(76%) followed by peanut(48%),hazelnut and pine-nut(43%), cashew(38%), pistacchio(33%) and walnut(24%). Nopositive reactions were observed.

We present a new safe nut-mix oral challenge test that could facilitate the nut allergymanagement, by reducing the number of day hospital appointments, school and workabsenteeism, health care costs as well as unnecessary restrictive diets.