A retrospective study of peanut and tree nut allergy: Sensitization and correlations with clinical manifestations

Abstract

Peanut (PN) and tree nut (TN) P eanut (PN) and tree nut (TN) allergies can be severe and account for a relatively high proportion of fatal food-induced anaphylaxis.1,2 These allergies can be lifelong 3 and appear to be increasing in prevalence, especially in children.4,5 The current prevalence of nut allergy (2%) has doubled in the past 10 years. 5PN and TN allergy are a major health concern.6 PN is a legume, the same family as beans such as soy and peas, 7 and is different from TNs. Studies have shown cross-reactive allergen epitopes between PNs and TNs 8,9 but whether this results in clinical cross-reactivity remains unclear. This cohort study investigated the correlation between PN and TN allergy, in terms of clinical allergic manifestations and in vitro sensitization (IVS). METHODSWe conducted a retrospective medical chart review (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) at the Allergy Clinic at University Hospital of Brooklyn. Cases of children (Ͼ3 years old) and adults who had PN and/or TN allergy (include cashew, walnut, almond, hazelnut, pistachio, or pecan) were reviewed. Presence of concurrent allergic disease including allergic rhinoconjunctivitis, asthma, and atopic dermatitis (AD) was also included in the database. This study was approved by the Institutional Review Board from State University of New York Downstate Medical Center. The data were collected without identifiers, and all of the information was kept confidential.The total number of organ systems involved in clinical reactivity was determined, including dermatologic (urticaria, pruritus, angioedema, swelling, and worsening of AD), respiratory (wheezing, throat tightness, shortness of breath, cough, and tight chest), gastrointestinal (nausea, vomiting, diarrhea, and abdominal pain), and neurological (dizziness and syncope). Degree of IVS was quantified as follows: 0, not reactive (IgE, Ͻ0.35 kU/L); 1, weakly reactive (IgE, 0.35-0.7 kU/L); 2, moderately reactive (IgE, 0.7-3.5 kU/L); 3, highly reactive (HR; IgE, 3.5-17.5 kU/L); 4, very highly reactive (VHR; IgE, 17.6 -100kU/L; Quest Diagnostics, Madison, NJ). For patients with multiple TN sensitivities by serum IgE, the greatest level of sensitivity was used in statistical analysis. Spearman correlation coefficients were generated to determine the relationship between total allergic reaction organ involvement and level of IVS.Statistical data analysis was performed using SAS Version 9.3 software (SAS, Cary, NC). RESULTSOf 1406 charts were reviewed; 76 (5.4% of 1406) patients were identified with self-reported PN or TN allergy.