Highly atopic children: formation of IgE antibody to food protein, especially peanut.

Highly atopic infants often form IgE antibodies toward multiple food protein in the first 2 years of life. They begin producing IgE antibody to inhalant allergens between the first and second year of life. We hypothesized that highly atopic children would be at significant risk of sensitization to peanut. We defined high atopy as serum IgE greater than or equal to 10 times 1 SD from normal plus multiple positive RASTs. In this study we have characterized the immunologic status of 141 patients by measuring total serum IgE and specific IgE to several allergens, including peanut. These data demonstrated that, independent of clinical history, a positive RAST to peanut was more common in the highly atopic category compared to the low atopy category. Significantly more patients who were highly atopic and had a positive peanut RAST had a positive RAST for egg or milk compared to low atopic patients. More significantly, 33 of the patients had never knowingly received peanut, yet 21 (63.6%) had a positive RAST for peanut, whereas seven (21.2%) had a peanut antibody in the highest RAST category. All these seven patients were considered highly atopic according to the definition above, and three were younger than 2 years of age. These results suggest that highly atopic infants are at special risk for sensitization to peanut, even when they have never received peanut, and that characterization of immunologic sensitization to milk, egg, and peanut will identify the highly atopic infant.(ABSTRACT TRUNCATED AT 250 WORDS)