Study Design Estimating the rate of food allergy in a population is challenging because
measuring food allergy on a large scale is difficult. True food allergy is defined by a specific,
reproducible, immunologically mediated clinical response upon exposure to allergen. Only
food challenge directly assesses the clinical response upon allergic exposure, but the
inherent risk to patients of food challenge, combined with the fact that it is time and staff
intensive, makes it untenable in general for large-scale studies of food allergy prevalence …