Prevalence and main characteristics of schoolchildren diagnosed withfood allergies in France

Background A cross-sectional, descriptive, questionnaire-based survey was conducted in Toulouse schools to determine the prevalence of food allergies among schoolchildren. Objectives The first goal of the survey was to estimate the prevalence of food allergies. The second goal was to determine the main characteristics of the allergies. Methods The questionnaires (3500) were distributed in 150 classes in eight schools. The return rate was 77.6% (2716). Results Of the 192 (7.0%) questionnaires with a 'Yes' response (report of a food allergy), 182 were retained as reporting true food allergies (6.7%). The cumulative and point prevalences were 6.7% [95% confidence interval (CI) 5.8-7.6] and 4.7% [95% CI 3.9-5.5], respectively. The point prevalences were 4.0% for the children aged 2-5 years, 6.8% for the children aged 6-10 years, and 3.4% for the children aged 11-14 years. The main foods reported as causing adverse reactions were cow milk (n=29, 11.9%), eggs (n=23, 9.4%), kiwis (n=22, 9.0%), peanuts (n=20, 8.2%), fish (n=19, 7.8%), tree nuts (n=19, 7.8%), and shrimp (n=13, 5.3%). The average age at which the allergies were detected was 3.4+/-2.8 years (with a range of 0.1-12 years). The clinical signs of the food allergies were cutaneous (n=153, 62.7%), digestive (n=74, 30.3%), respiratory (n=17, 6.9%), and anaphylactic shock (n=12, 4.9%). Conclusion While well aware of the biases inherent in this type of study, we estimated the cumulative and point prevalences of food allergies in a population of schoolage children in Toulouse at 6.7% and 4.7%, respectively. Cow milk, eggs, and peanuts were the main foods reported as causing allergies. Exotic fruits, shellfish, and tree nuts appeared to be relatively new allergens.