Prevalence of clinic-defined food allergy in early adolescence: The SchoolNuts study

Background: Rising rates of food-induced anaphylaxis have recently been shown in the adolescent age group, following earlier descriptions of a rise in children younger than 5 years. However, few population-based studies have examined the prevalence of food allergy in adolescence using objective measures such as oral food challenge (OFC).

Objective: We sought to determine the prevalence of food allergy among a population-based sample of 10- to 14-year-old adolescents using clinical evaluation including OFC to confirm the diagnosis.

Methods: Schools were randomly selected from greater metropolitan Melbourne, Australia. Students aged 10 to 14 years, and their parents, were asked to complete a questionnaire regarding the adolescent's food allergy or food-related reactions. Clinic evaluation, which consisted of skin prick tests and OFC where eligible, was undertaken if students were suspected to have current food allergy from parent response. Among 9816 students assessed, 5016 had complete parent response and clinic evaluation when eligible. An additional 4800 students had student questionnaires only.

Results: The prevalence of clinic-defined current food allergy based on history, sensitization data, and OFC results was 4.5% (95% CI, 3.9-5.1), with the most common food triggers being peanut, 2.7% (95% CI, 2.3-3.2), and tree nut, 2.3% (95% CI, 1.9-2.8). Among the additional group of 4800 adolescents who had only self-reported food allergy status available, the prevalence of self-reported current food allergy was 5.5% (95% CI, 4.9-6.2), with peanut, 2.8% (95% CI, 2.3-3.3), and tree nut, 2.3% (95% CI, 1.9-2.8), the most common.

Conclusions: Approximately 1 in 20 10- to 14-year-old school students in Melbourne has current food allergy. This high prevalence suggests that the previously reported rise in food-induced anaphylaxis in this age group may reflect an increasing prevalence of food allergy rather than simply increased reporting of anaphylaxis.