Bronchial sensitivity to histamine in former asthmatics: redevelopment of symptoms during a year of followup.

The aim of this protocol was to study bronchial responsiveness in 23 former asthmatics who were free of symptoms for at least 5 years. Bronchial hyperreactivity (BHR) was evaluated with histamine challenge test and the results were compared with those of 20 normal subjects and 20 current asthmatic patients. Among the former asthmatics 65% fulfilled the criteria of BHR. During 1 year of followup, two former asthmatics redeveloped asthma symptoms. Interestingly, one patient had no BHR when initially tested. These findings suggest that the absence of BHR does not guarantee the nonrecurrence of asthma symptoms in former asthmatics.