Defining Challenge-Proven Coexistent Nut and Sesame Seed Allergy: A Prospective Multicenter European Study

To determine the rates of co-existent allergy between peanut, tree nuts, and sesame.

122 children aged 0 to 16 years with a confirmed allergy to peanut, tree nut(s), and/or sesame seed.

Children aged 0 to 16 years with at least one confirmed allergy to peanut, tree nut, or sesame seed underwent sequential diagnostic food challenges to all other nuts and sesame seed.

Overall, the rate of coexistent peanut, tree nut, and sesame seed allergy was 60.7% (74/122). Clear differences were seen between the 3 study sites: peanut allergy was more common in London, cashew and pistachio allergies were more common in Geneva, and walnut and pecan allergies were more common in Valencia. Strong correlations were found between cashew-pistachio, walnut-pecan, and walnut-pecan-hazelnut-macadamia clusters. Age (>36 months) and center (Valencia > Geneva > London) were associated with an increased odds of multiple nut allergies. By pursuing the diagnostic protocol to demonstrate tolerance to other nuts, participants were able to introduce a median of 9 nuts.

The study found a higher rate of coexistent nut and sesame seed allergies than previously reported. Performing sequential food challenges is labor intensive and can result in severe allergic reactions but can also reduce dietary restrictions. Age was a significant predictor of multiple nut allergies, suggesting a secondary spread of nut allergies in older children.

This is a great study. The authors used the word “labor intensive,” but that is an understatement. Although the sample of 122 does not sound high, when multiplied by actually doing challenges to peanut, sesame, and nine tree nuts, the work that went into providing these data is extraordinary, and the data are invaluable. Rates of coexistent allergy between these foods are commonly reported but have been derived primarily from retrospective studies that include only a limited number of tree nuts or were not based on oral food challenges.