Diagnosis of Multiple Inhalant Allergies in Children by Radioimmunoassay

Abstract

A series of 302 patients reporting immediate hypersensitivity symptoms to inhalant allergens was evaluated by both puncture skin testing and the radioallergosorbent test (RAST) using 13 common inhalant allergens. Agreement between the two tests varied from 71% to 93% for the various allergens and averaged 82%. The best correlation, 93%, was obtained with mixed grass pollen allergens. If a purified allergen, rye group I, was used the correlation rose to 97.5%. The correlation was 88% for the mold Alternaria, and the negative-sera did not become positive when tested over a wide range of dilutions. Fifty-eight percent of the patients with house dust allergy reacted to house dust mite (Dermatophagoides farinae). Correlations of 71% to 93% were obtained with ten weed and tree pollens. The only patients in whom positive RASTs were found with negative skin tests to the same antigen had either severe atopic dermatitis or decreased skin response to exogenous histamine. Sera from a group of 20 patients with positive allergy history but negative skin tests also had negative RAST. The radioallergosorbent test appears to add little information to that obtained by a comprehensive allergy history and puncture skin tests in the great majority of children with inhalant allergy. The only exceptions were children with severe atopic dermatitis, suppressed skin reactivity or dermatographism.