Quantitative skin prick tests and serum IgE antibodies in atopic asthmatics

We assessed the immediate skin reactivity to Dermatophagoides pteronyssinus in children with atopic asthma in order to determine the intensity of the skin reaction, its time course and the end-point allergen concentration. We also examined the correlation between the total and D. pteronyssinus-specific IgE levels and the severity of asthma. Asthmatic children were age- and sex matched to nonatopic children. Significant eosinophilia and elevated serum IgE levels were correlated with the presence of asthma but bore no relation to the severity of the disease. The average end-point allergen concentration was approximately 50 allergy units (AU). The mean wheal diameter ranged from 6.1 mm in mild asthmatics to 7.1 mm in severe cases; this difference, however, was not significant. Most of the patients (85%) reported local pruritus within 120 seconds after allergen injection. The time lag until the start of the reaction and the wheal diameters were correlated with the levels of D. pteronyssinus-specific serum IgE antibodies, and with the end-point allergen concentration. These two variables therefore provide good indicators of the time course and the extent of the skin test reaction in individuals sensitive to the allergen tested.