Correlation of negative skin-prick test results for tree nuts and successful tree nut challenges among children with peanut allergy

Abstract

Background: Children with peanut allergy are regularly instructed to avoid all tree nuts. However, children with peanut allergy are likely not allergic to all tree nuts. Objective: In our cohort of patients with peanut anaphylaxis and who underwent oral immunotherapy, we sought to determine the correlation of skin-prick testing (SPT) results for tree nuts and the likelihood of successfully passing a tree nut challenge. Methods: SPT was performed for peanut and tree nuts (macadamia, pine nut, coconut, hazelnut, brazil nut, cashew, pecan, walnut, pistachio, almond) in 27 patients with known peanut allergy. The probability of a negative SPT result (wheal < 3 mm) for each nut was determined. Results: All the patients demonstrated positive results in peanut allergy diagnostics in SPT, component testing, or food challenge. Only 15.4% of the patients had a positive SPT result to peanut alone. Macadamia, pine nut, and coconut SPT had a probability of negative SPT results of 0.97, 0.97, and 0.91, respectively. The odds ratio for this group having a negative SPT was 46.22. For hazelnut, brazil nut, and cashew, the probability of a negative SPT result was 0.81, 0.77, and 0.73, respectively. Pecan, walnut, and pistachio had odds ratios of 0.68, 0.68, and 0.64, respectively. All the patients with macadamia, pine nut, and coconut negative SPT results subsequently passed 9-g food challenges without oral immunotherapy. Conclusion: Despite current recommendations to avoid all tree nuts for patients with peanut allergy, the majority of patients with peanut allergy had negative SPTs and food challenges to certain tree nuts, especially macadamia, pine nut, and coconut. This pattern was seen despite most patients having multiple nut sensitizations.