[Age-related changes of IgE-mediated allergic reaction in patients with late onset asthma--relationship between IgE-mediated allergy and age at onset].

We examined age-related changes in the IgE-mediated allergic reaction in patients with late onset asthma, whose asthma first occurred at over 40 years. 1. The number of patients with a high serum IgE level (over 300 IU/ml) was larger in patients with an age of onset between 40 and (40-49 years group) and in patients older than 60 at age of onset (60-year group) than in patients with an age of onset between 50 and 59 (50-59 year group). 2. A positive RAST score to house dust mite (HDm) allergen was more frequently found in the 40-49 year group and in the 60- year group than in the 50-59 year group. Frequency of positive RAST score to HDm in the 50-59 year group was significantly lower (p < 0.01) than in early-onset asthma patients (age at onset less than 39 years). 3 Frequency of family history of asthma in the 50-59 years group was high, being equal to that of early-onset asthma patients. 4 In the 50-59 year group, the frequency of severe asthma was comparatively higher than that of the other groups. The frequency of IgE-mediated allergic reaction changed in regard to age of onset of asthma, and allergic reactions in late-onset asthma partially resembled those of early-onset asthma. These results suggest that an atopic constitution is related to the onset of bronchial asthma in the elderly.