BACKGROUND: Hazelnut is the most frequent cause of tree-nut allergy, but up to half of all children with hazelnut allergy additionally suffers from peanut allergy. Our aim was to identify diagnostic values of the most promising serological markers (Cor a 9 and Cor a 14) and to address the influence of concomitant peanut allergy and PR10 sensitization.
METHOD: We included 155 children suspected off hazelnut allergy and challenged according to guidelines. Concomitant allergy to peanuts was verified or ruled out by challenge. Skin Prick Test, s-IgE and CRD to hazelnut, peanut, PR10 and LPT protein families were measured using ImmunoCap.
RESULTS: Sixty-five children had a positive hazelnut challenge, and 60% of these also had concomitant peanut allergy. Children allergic to hazelnut were sensitized to Cor a 9 and Cor a 14; peanut allergic children to Ara h 2. Sensitization to PR10 protein components were seen in 45% of all included children, irrelevant of allergy to peanut or hazelnut. A cutoff > 0.72 kU/L of IgE towards Cor a 14 diagnosed 87% correctly, making Cor a 14 the superior serology markers. However, 9 hazelnut allergic children were primarily sensitized to Cor a 9.
CONCLUSION: Concomitant peanut allergy is common in hazelnut allergic children, but decision points as well as diagnostic values for Cor a 14 are not affected. We found 3 independent and well-characterized serotypes; hazelnut allergic children sensitized to Cor a 14, peanut allergic children sensitized to Ara h 2 and children sensitized to birch pollen protein Bet v 1. This article is protected by copyright. All rights reserved.