Tree Nut and Peanut Allergy in a Portuguese Pediatric Cohort- Clinical Characterization and Anaphylaxis PredictorsLeonor Esteves

Background: Tree nuts and peanuts (TN/P) are frequent causes of anaphylaxis in children. Aim: to characterize a Portuguese pediatric cohort with TN/P allergy and to assess skin tests (ST), specific IgE (sIgE) and molecular components (mcIgE), as well as sIgE/total IgE ratio’s utility in anaphylaxis prediction. Methods: Retrospective study (2017-2021) of pediatric patients with TN/P allergy, grouped according to reaction severity (anaphylaxis–G1 vs milder reaction–G2). ST mean papule diameter (MPD), sIgE (ImmunoCAP ® ), mcIgE (ISAC ® ) and sIgE/total IgE ratio were compared (SPSS ® , p < 0.05: statistically significant). Results: 98 patients, 64% male, 88% concomitant allergic disorder, 40% allergy family history. Major culprit nuts: peanut (63%), hazelnut (59%) and walnut (53%). Index reaction manifestations were mostly cutaneous (46%), followed by anaphylaxis (36%). Chestnut and cashew sensitizations were significantly associated with anaphylaxis (OR=5.023, p=0.002; OR=2.901, p=0.018). MPD was higher in G1 for almond, cashew and pistachio (p < 0.05). sIgE was not a good severity predictor for any TN/P, however, a significantly higher value of sIgE/total IgE ratio was found in G1 for walnut (p=0.023). mcIgE was obtained in 49%: peanut Ara h2 and Ara h6 were more represented in G1 (2.8 vs 0 ISU-E, p=0.042; 1.3 vs 0 ISU-E, p=0.020). Conclusion: Peanut, hazelnut and walnut were the most frequent nuts. Anaphylaxis was the first manifestation in 36%, significantly higher in chestnut and cashew allergic children. MPD should be valued not only for diagnosis, but also for anaphylaxis risk prediction in almond, cashew and pistachio allergic patients. sIgE/total IgE ratio seems to be useful in anaphylaxis prediction.