Exercise-food challenge test in patients with wheat-dependent exercise-induced anaphylaxis

Background: Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a severe and potentially life-threatening food allergy. Diagnosis of WDEIA is challenging because reactions are not always reproducible. Objective: This study aimed to evaluate the positivity rate of exercise-food challenge test at our allergy unit in order to confirm the diagnosis, and to investigate the effect on the episode of reactions after the test. Methods: This retrospective evaluation included patients aged 5-60 years who presented at the pediatric and adult allergy units of Siriraj Hospital during 2014-2018 with a convincing history of WDEIA and who underwent a 4-day exercise-food challenge test. Demographic data, challenge test result, and episodes of the reaction before and after the challenge test were obtained. Results: Fourteen of the 17 patients that were enrolled were included in the analysis. The 3 excluded patients were found to have IgE-mediated wheat allergy. Median age and time to diagnosis was 18.3 years (range: 10.5-43.4) and 1.8 years (range: 0.3-6.2). History of recurrent acute urticaria before the onset of anaphylaxis was reported in 5 patients (35.7%). Exercise-food challenge test was positive in 10 patients (71.4%). Median mean number of exacerbations per year before and after the confirmation test was 2 (range: 1-10) and 1 (range: 0-3), respectively. Conclusion: For WDEIA, time to diagnosis was delayed, and one-third of patients had recurrent acute urticaria proceeding anaphylaxis onset. Our exercise-food challenge test could be utilized safely in both children and adult and able to elicit symptoms in two-third of patients.