Evaluation of the safety of multiple nut oral food challenges in the management of nut allergy.

Background. Tree nut and peanut allergy are common, and often persistent conditions, that significantly affect quality of life. Multiple nut avoidance is common due to cross-reactivity concerns but may cause unnecessary restrictions. Data regarding multiple nut oral food challenges (MN-OFC) remains limited. Our aim was to evaluate the safety and clinical impact of MN-OFC in the management of tree nut and/or peanut allergy. Methods. Retrospective analysis of 25 patients who underwent MN-OFCs between 2022 and 2024 at a tertiary-level Allergy Department. Patients with profilin and/or PR-10 sensitization were excluded. Diagnostic evaluation included clinical history, skin prick tests (SPT), skin prick-to-prick tests (SPPT), and specific IgE measurement (ImmunoCAP® and/or ImmunoCAP™ ISAC). MN-OFC, using incremental dosing and extended observation, were conducted in patients with negative results for nut-specific seed storage proteins and negative PPT with the suspected nut. Results. A total of 26 MN-OFC were performed, involving 87 nuts. Sensitization to storage proteins was detected in 54% of patients, and to lipid transfer proteins in 17%. Despite negative SPPT, 16% had positive SPT. MN-OFC were negative in all patients. Prior to OFC, patients excluded a median of 6 nuts from their diet, which decreased to 2 post-challenge. Use of MN-OFC avoided 261 hours of individual oral food challenge procedures. Conclusions. In this population, MN-OFC is a safe, time-efficient, and clinically valuable strategy for ruling out tree nut and/or peanut allergy in selected patients. They support more personalized dietary recommendations and reduce unnecessary avoidance, while optimizing healthcare resources use.