EXTRINSIC AND INTRINSIC ASTHMA FROM CHILDHOOD TO ADULT AGE - A 10-YR FOLLOW-UP

Background: Asthma constitutes one of the most common chronic diseases in childhood, yet little is known about the factors that determine th e outcome in childhood asthma. The purpose of this study was to descri be various factors of potential importance for the outcome in children with intrinsic and extrinsic asthma. Methods: Of 85 consecutive child ren, 5-15 years of age with asthma, 70 (82%) participated in a IO-yr f ollow-up examination. At the time of referral, all children underwent certain tests for asthma (case history, total IgE, skin prick tests, r adioallergosorbent (RAST) tests and specific bronchial provocations). On the basis of these tests, 24 children had intrinsic asthma and 46 c hildren had extrinsic asthma. Results: At the follow-up examination, 6 0 of the 70 adults (86%, 20 with intrinsic asthma) had current symptom s; 54 of the 60 (90%; 18 with intrinsic asthma) were receiving mainten ance therapy. Both FEV(1) %predicted and FEV(1)/FVC increased signific antly (from 73% +/- 19% to 92% +/- 17% and from 75% +/- 13% to 80% +/- 12% respectively) from childhood to early adulthood (P<0.0001 and P<0 .001, respectively); a matching amelioration of symptoms was observed (P<0.0001). Adults with current symptoms had a significantly lower FEV (1) %predicted at the time of follow-up (90% +/- 2% vs. 100% +/- 4%, P <0.02) but not in childhood (73% +/- 20% vs. 71% +/- 10%) than adults who had ceased wheezing. Conclusions: In children with intrinsic asthm a, the outcome seems to be predicted by a combination of the initial f requency of symptoms (P=0.04), initial FEV(1) (P=0.002), active smokin g (P=0.001) and age at onset of respiratory symptoms (P=0.001), wherea s the initial FEV(1) (P<0.001) seems to be a strong predictor for the outcome in children with extrinsic asthma. These findings suggest that the pathogenic mechanisms underlying intrinsic and extrinsic asthma i n children may differ.