Sesame allergy diagnosis: utility of current diagnostic tests
Published online: November 28, 2019
Sesame allergy is increasingly recognized as a cause of severe food allergy, affecting 0.1-0.8% in the Western countries. Sesame allergy can be life-threatening and is persistent in more than two thirds of patients. Recognizing the growing importance of sesame allergy, the United States Food and Drug Administration is considering including sesame among major food allergens covered by the Food Allergen Labeling and Consumer Protection Act of 2004.
Oral food challenge (OFC) remains the gold standard for food allergy diagnosis but is resource-intensive, carries a risk of anaphylaxis, and has limited availability thus justifying the search for the alternative laboratory diagnostic tests.
In an article recently published in The Journal of Allergy and Clinical Immunology in Practice Saf and colleagues compared the currently available laboratory diagnostic tests to the outcomes of sesame OFC.
In the largest study of sesame allergy to date, a total of 341 pediatric patients underwent a sesame OFC in the Elliot and Roslyn Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai in New York, NY, USA. Overall, 106 (31%) reacted during sesame OFC. The majority of patients (75%) had no prior reaction to sesame and avoided sesame due to another food allergy (e.g. peanut allergy). Of them, 25% had a confirmed allergy after sesame OFC. The risk of a reaction during sesame OFC was double (50%) among the patients with a prior reaction to sesame.
In the overall study population, skin prick test (SPT) with commercial sesame extract performed better at predicting reactions during OFC compared to sesame serum allergen-specific Immunoglobin E (sIgE). SPT wheal size equal or greater to 6mm correctly identified more than 50% of the patients who reacted during sesame OFC, wheal size 14 mm identified more than 95% of the reactive patients. In a smaller subset of 30 patients, the component Ses i 1-sIgE, the major allergenic protein in sesame seeds, had a better accuracy compared to both sesame SPT and whole sesame sIgE. However, reactions during sesame OFC were observed even if the patient had a negative sesame SPT or an undetectable sesame-sIgE.
In this study, sesame SPT is a more accurate predictor of sesame allergy compared to whole sesame sIgE. Sesame component Ses i 1-sIgE appears promising and should be further studied regarding its diagnostic accuracy.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.