PURPOSE OF THE STUDY.
To show characteristics and outcomes of oral food challenges (OFCs) in patients with tree nut (TN) sensitization with or without documented tree nut allergy and to help understand the relation between tree nut sensitization (by skin prick testing [SPT] and specific immunoglobulin E [sIgE]) and OFC outcomes.
All open TN OFCs conducted at the University of Michigan Allergy and Immunology clinics between 2007 and 2015. Patients included in the study had a mean age of 4.5 years. Patients who had TN SPT and or TN sIgE testing before the challenge were included. Patients with a history of a non-IgE–mediated food allergy were excluded.
Retrospective analysis was performed by using International Classification of Diseases, Ninth Revision and CPT codes for OFCs. TN SPT wheal size, TN sIgE, any coexisting food allergy, allergic diseases, and OFC reactions were obtained from chart review. Subjects were classified as allergic to TN, sensitized to TN (with no history of allergy to any TN), or avoiding TN despite a lack of sensitization or reaction history. TN-allergic patients did not undergo an OFC to the TN they were allergic to; instead, they underwent OFCs to other TNs without known histories of allergic reaction. National Institutes of Allergy and Infectious Disease and Food Allergy & Anaphylaxis Network anaphylaxis criteria were used to assess documented OFC outcomes.
Of 156 TN OFCs in 109 patients, 86% were negative challenges. Seventy-six percent of patients with a specific TN allergy had a negative challenge to another TN. Among patients with TN sensitization only, 91% had a negative challenge. A negative challenge was seen for 89% of patients with TN sIgE <2 kUA/L (n = 124) and for 69% of patients with sIgE ≥2 kUA/L (n = 16). In patients with a TN SPT wheal ≥3 mm (n = 44), 61% had a negative challenge. Among patients with peanut allergy and TN co-sensitization, 96% had a negative TN challenge. Sixty percent of OFCs were delayed longer than 12 months.
TN OFCs are frequently negative, even in patients with sensitization, as demonstrated by SPT or sIgE testing. Most patients with peanut allergy and specific TN allergy and/or sensitization are able to tolerate selected TNs.
This retrospective study provides useful data regarding outcomes for TN OFCs in patients with a tree nut allergy or sensitization from a single academic center. Additional studies would be beneficial to provide guidance for clinical decision-making regarding when to refer patients with a history of peanut or specific TN allergy or sensitization for consideration of OFCs to other TNs.
- Copyright © 2017 by the American Academy of Pediatrics