Inter-relation of immediate and late asthmatic reactions in childhood.

Following bronchial provocation tests with inhalent allergens, late asthmatic reactions (LAR) frequently follow immediate asthma reactions (IAR). This study of atopic asthmatic children demonstrated that patients could show IARs to one allergen, ryegrass extract, but isolated LARs without any preceding immediate response when challenged with an unrelated allergen extract of D. pteronyssinus. The patients' degree of skin sensitivity to the concentration of extract inhaled appeared one factor which determined whether an isolated LAR or IAR followed allergen inhalation.