Peanut, tree nuts and sesame seed allergies: Does a single nut allergy necessitate the dietary eviction of all nuts?
Monday, March 6, 2017: 2:30 PM
Thomas B. Murphy Ballroom 3-4 (Georgia World Congress Center, Building B)
Jean.Christoph Caubet, MD, , , , , ,
Rationale: Although there is a large cross-sensitivity by IgE testing among tree nuts and/or peanut, the clinical relevance remains unknown. In many allergy centres, allergy to either peanut or a tree-nut leads to recommendation for the avoidance of all nuts and often also sesame seed. 

Methods: Based on up to 11 sequential nut challenges in each patient, we aimed to identify which nut allergic patients should apply selective or complete dietary avoidance of all nuts. We included children aged from 0 to 16 years with a convincing history of IgE-mediated systemic allergic reaction to ≥1 nut within last 12 months and skin prick tests (SPT) ≥8 mm and/or IgE ≥15kU/L (26kU/L for sesame) or a positive oral food challenge to the nut. 

Results: Ninety-two children were prospectively recruited in Geneva and London. Fifty-six percent of patients were allergic to more than one nut. We confirmed the strong association between pistachio and cashew nut allergy (84%), as well as between pecan, hazelnut and/or walnut allergy (59%). SPT had a high negative predictive value for the different types of nuts. Regarding hazelnut and peanut, specific IgE to Cor a 14 and Ara h 2, respectively, were the better discriminating factors with larger ROC areas under the curve (84% and 95%, respectively). 

Conclusions: Introduction of different nuts may decrease unnecessary dietary avoidance of peanut, tree-nuts and sesame seed. For most nuts, our data showed that SPT and/or specific IgE to recombinant allergens had a high diagnostic value to discriminate between allergic versus tolerant patients.