Respiratory causes are more common and include infections, smoking, obstructive airway disease, atelectasis, cystic fibrosis, occupational disease, and emphysema.
Non-respiratory causes include post-nasal drip from sinusitis, gastro-oesophageal reflex, cardiac disease, drugs like ACE inhibitors, pericardial and diaphragmatic disease, and psychological factors.
The three commonest causes of recurrent cough are post-nasal drip, asthma, and reflux.
