Food-specific serum immunoglobulin E measurements in children presenting with food allergy

Abstract

BackgroundIn children with food allergy, multiple food-specific serum IgE levels to common food allergens are frequently measured. ObjectiveTo compare food-specific serum IgE measurements among common food allergens in children with food allergy to determine the characteristics of the measurements, their ability to discriminate between foods associated and not associated with a presenting clinical reaction, and their change over time. MethodsA retrospective analysis was conducted of food-specific serum IgE to cow's milk, egg white and yolk, peanuts, almond, and soy, for up to 3 subsequent measurements, in 291 children with food allergy. A food-specific serum IgE level lower than 0.35 kU/L was considered a negative measurement. The correlation of IgE measurements with presenting symptoms was conducted for each food in 172 children. ResultsOf 1,312 food-specific serum IgE measurements, 69.8% were positive. The median (interquartile range) IgE level for foods associated with the presenting complaint was 7.3 kU/L (2.7–31) and that for foods not associated with a clinical complaint was 2.2 kU/L (0.38–13). The difference was statistically significant (P = .01) only for cow's milk. Specific IgE levels were highest for peanuts, followed by cow's milk, eggs, soy, and almonds, and trended upward over time. ConclusionIn children presenting with clinical symptoms of a reaction to a food allergen, measurements of food-specific serum IgE to other common food allergens are commonly positive. An increase in food-specific serum IgE occurs over time.