[Bronchial hypersensitivity to histamine in asthmatic children longitudinal study from first visit to remitted state]

In order to examine the changes in bronchial hypersensitivity, histamine inhalation tests were evaluated in 27 asthmatic children who remitted. The respiratory threshold to histamine (RT-Hist) 2-3 yrs after remission was higher than in the initial test, in their worst periods of the asthma and just before remission (p < 0.001, p < 0.001, p < 0.005, respectively). Eleven subjects (40.7%), showed no improvement of bronchial hypersensitivity 2-3 yrs after remission (RT-Hist was 1250 micrograms/ml or lower). In this group, the asthma score per year two and three years before symptom-free state was higher than in the group with improved bronchial hypersensitivity (p < 0.05). There was no significant difference between % fall of FEV1.0 in RT-Hist in the worst periods of the asthma and 2-3 yrs after remission. FEV1.0/VCP, %V50, %V25 and V25/Ht 2-3 yrs after remission were higher than those in the worst periods of the asthma.