Chronic cough: clinical characteristics and etiologies of 510 cases.

Objective: To investigate the clinical features and underlying etiologies of chronic cough (CC).

Methods: Five hundred and ten CC patients were enrolled. The phases, characteristics and associated clinical manifestations of CC among the gastroesophageal reflux cough (GERC), cough-variant asthma (CVA), and upper airway cough syndrome (UACS) groups were compared, and the diagnostic values of each group were evaluated by multiple regression analysis.

Results: In the 510 patients, 404 had CC with single etiology-GERC (n = 175), CVA (n = 134), and UACS (n = 95). The characteristic features of GERC included gastric acid backflow symptoms such as sour-tasting regurgitation, heartburn, endoscopic esophagitis, poststimulation cough, frequent throat clearing, daytime mono-cough, and feelings of heaviness and pain in the chest. Patients with CVA typically exhibited sensitivity to smog and other irritants; the cough occurred mostly at night, and was associated with positive bronchodilator and provocation test results. The typical features of UACS included a history and/or symptoms of rhinitis, retropharyngeal postnasal drip, and wet cough occurring mostly during the daytime. The diagnostic specificities of above factors were >70%.

Conclusions: The most common causes of CC include GERC, CVA, and UACS, and their diagnosis is based on the characteristics of the underlying disease.