Abstract

The prevalence of atopic diseases and bronchial reactivity to histamine and methacholine was determined in 36 patients with bronchiectasis and in 36 control patients matched for age, sex, and smoking history. There was no difference in the prevalence of asthma, other atopic diseases, family history of atopic diseases, or positive responses to skinprick tests (nine versus five) in the two groups. The prevalence of bronchial hyperreactivity, however, was significantly higher in the group with bronchiectasis than in the control group for both histamine (7 v 0 patients) and methacholine (6 v 0 patients). The group with bronchiectasis had more airflow obstruction (mean FEV1 67% predicted), but there was no correlation between spirometric indices and log PD20 (the log dose of histamine or methacholine causing a 20% fall in FEV1). This suggests that, although reduced airway calibre may be a factor underlying bronchial hyperreactivity in bronchiectasis, it is not the only mechanism. Further studies are needed to determine whether bronchial hyperreactivity has a causative role in the pathogenesis of bronchiectasis or whether it occurs as a result of the disease.