Change in airway responsiveness to inhaled house dust from childhood to adulthood

Between 1966 and 1969, housedust (HD) inhalation provocation tests were performed in 119 children with asthma. Between 1984 and 1987, 101 of the 119 subjects (85%) were reinvestigated. Thirty-one of these 101 adults who participated in a study on the outcome of childhood asthma were rechallenged with HD after a mean interval of 16 years to establish the change in airway responsiveness to HD from childhood to adult life. In the childhood study in these 31 subjects, six had no response (NAR); six, an early response (EAR); eight, a late (LAR); and eleven subjects, an EAR followed by an LAR (dual asthmatic response [DAR]) to the inhalation of HD. In the second survey, two of the subjects with NAR in the first study had a bronchoconstrictor response to HD. Five subjects with an EAR or an LAR response in childhood had NAR as an adult. The eleven subjects with a DAR during childhood also had a response to HD as an adult; five had an EAR, and six adults again had a DAR. Eleven of the 13 adults (85%) with current respiratory symptoms had a response to HD during the second survey. Although they were symptom free, 11 of the other 18 adults (61%) responded on inhalation of HD. One of the 18 subjects without (6%), and six of the 13 subjects (46%) with current respiratory symptoms, had a provocative concentration of histamine in FEV1 10% of baseline less than or equal to 16 mg/ml. We conclude that, although respiratory symptoms disappear in one half the children with asthma and although adults may believe that they have outgrown their disease, adults still have the potency to respond to inhaled allergens. Most children do outgrow their respiratory symptoms but not the susceptibility of their airways to allergens.