A study of clinical features of cough variant asthma.

Patients with cough variant asthma (CVA) and classic asthma are frequently among subjects who present at clinics complaining of a chronic persistent cough. To reveal the features of CVA, we examined the differences in the clinical appearance between CVA and classic asthma. Ten CVA subjects and 11 classic asthmatics were enrolled in the study; they were recruited among patients who presented at the National Minamiokayama Hospital complaining of a chronic cough. The number of eosinophils in peripheral blood was 256 +/- 45.8/microl in CVA and 400 +/- 123/microl in classic asthma. Eosinophils represented 67% of the cells of sputum in CVA and 82% in classic asthma. Bronchial responsiveness to methacholine was Dmin 1.37 +/- 0.56 U in CVA and 0.71 +/- 0.46 U in classic asthma. There was no significant difference in these three parameters. There was only a significant difference in V25 between CVA and classic asthma, 80.0 +/- 6.9 and 52.2 +/- 10.0%, respectively. Eosinophil inflammation was almost the same in both CVA and classic asthma.