[Extrinsic and intrinsic asthma from childhood to early adult age. A 10-year follow-up]

Abstract

The purpose of this study was to describe factors of potential importance for the outcome in children with intrinsic and extrinsic asthma. Of 85 consecutive children, five to 15 years of age, with asthma, 70 (82%) participated in a ten year follow up examination. At the time of referral all children underwent certain tests for asthma (case history, total IgE, skin prick tests, radioallergosorbent tests (RAST) and specific bronchial provocations). On the basis of these tests 24 children had intrinsic asthma and 46 extrinsic asthma. At the follow up examination 60 of the 70 adults (86%; 20 with intrinsic asthma) had current symptoms; 54 of the 60 (90%; 18 with intrinsic asthma) were receiving maintenance therapy. Both FEV1 %pred (from 73% +/- 19% to 92% +/- 17%) and FEV1/FVC (from 75% +/- 13% to 80% +/- 12%) increased significantly from childhood to early adulthood (p < 0.0002 and p < 0.001, respectively); a corresponding amelioration of symptoms was also observed (p < 0.0001). In children with intrinsic asthma the outcome seems to be predicted by a combination of the initial frequency of symptoms (p = 0.04), initial FEV1 (p = 0.001), active smoking (p = 0.001) and age at onset of respiratory symptoms (p = 0.001), whereas the initial FEV1 (p < 0.001) seems to be a strong predictor for the outcome in children with extrinsic asthma. These findings suggest that the pathogenetic mechanisms underlying intrinsic and extrinsic asthma in children may differ.