Bronchodilator-resistive cough in atopic patients: bronchial reversibility and hyperresponsiveness

The number of atopic patients presenting only chronic non-productive cough appears to be increasing. This study was conducted to confirm the existence of non-asthmatic cough associated with atopy. We prospectively examined atopic findings, therapeutic effects of inhaled procaterol, azelastin, and/or glucocorticoids, improvement of FEV1 by bronchodilator therapy and bronchial responsiveness to methacholine in 20 patients. The cough was relieved by inhaled procaterol in 10 patients (Group 2) but not in the other 10 patients (Group 1). The increase in FEV1 by inhaled salbutamol following aminophylline injection was significantly less in Group 1 than in Group 2. Bronchial responsiveness to methacholine was normal in Group 1 while that in Group 2 was hyperreactive. These findings indicate that there is atopic non-asthmatic bronchodilator-resistive cough (Group 1) which is a different entity from bronchodilator-responsive cough (Group 2), or the so-called "cough variant asthma".