Changing etiological frequency of chronic cough in a tertiary hospital in Shanghai, China

Chronic cough is defined as cough lasting for ≥8 weeks with a normal chest radiograph, and its incidence is about 9.6%, or even up to 18.1% in certain areas (1). It negatively affects the quality of life of patients and its treatment has been a challenge in clinical practice (2). The common causes of chronic cough are cough variant asthma (CVA), upper airway cough syndrome/postnasal drip syndrome (UACS/PNDs), non-asthmatic eosinophilic bronchitis (NAEB), gastroesophageal reflux-related chronic cough (GERC) and atopic cough (AC) (3,4). These causes account for 70–95% of chronic cough (5)