The Food Challenge Risk Index: Predicting Positive Open Food Challenges to Milk, Egg, and Peanuts in Children

Abstract

Suspected food allergy is commonly encountered. Diagnosis requires skin testing, food-specific immunoglobulin E (IgE), and ultimately a food challenge. Previous studies determined food-specific IgE threshold levels predicting greater than 95% of the patients with a positive food challenge. However, if the food-specific IgE level is less than the threshold, a food challenge is required. Oral food challenges are time consuming, and they subject patients to allergic reactions. The aim of this study was to develop a food challenge risk index (FCRI) to predict positive food challenges. Fifty-five open food challenges were reviewed retrospectively. Skin prick tests, food-specific IgE levels, and time since last reaction were employed to develop a formula. The FCRI = [3 × skin prick test wheal (mm) + 10 × food-specific IgE level − time since last reaction (months)]. The FCRI value was compared to the food challenge results. Threshold levels chosen were 15, 20, and 25 for milk, egg, and peanut, respectively. Comp...