Onset of nut allergy in a pediatric cohort: clinical and molecular patterns. AFRUSEN study

Abstract

Background: Nut allergy is a growing problem, but little is known about its onset in children. Objective: Characterize the onset of nut allergy in Southern European children. Methods: Consecutive patients up to 14years of age who presented to allergy departments with an initial allergic reaction to peanut, tree nut, or seed were included. An allergy workup including clinical history, food challenge, SPT, and whole-extract sIgE and ImmunoCAP 112-ISAC assay were performed. Results: Of the 271 children included, 260 were first diagnosed with nut allergy at age 6.5years, 11.8(±21.2SD) months after the index reaction. The most common culprit nuts at onset were walnut (36.5%), peanut (28.5%), cashew(10.4%), hazelnut (8.5%), pistachio (5.4%), and almond (5%). Peanut-allergy onset was more frequent in children ≤6y.o. and walnut in those >6y.o. (p=0.032). In 65% of cases, the allergic reaction occurred the first time the patient consumed the nut, and 35% of reactions were anaphylactic. Overall, nut polysensitization was detected by SPT in 64.9% of patients, though this rate was lower among walnut- (54.7%) and peanut (54.1%)-allergic children (p<0.0001). Sensitization to 2S albumins was predominant (75%), specially Jug r1 (52.8%), whereas LTPs was less relevant (37%). Conclusion: In our population, the onset of nut allergy occured around 6years of age, slightly later than that reported in Anglo-Saxon countries. Walnut was the main trigger, followed by peanut and 2S albumins storage proteins, especially Jug r1, are the most relevant allergens. This study will help guide management and may contribute to preventive strategies in pediatric nut allergy.