Cough is a defensive, protective reflex. When a cough persists without an obvious respiratory irritant (eg. chest infection), cough becomes a concern to both patient and physician.

Possible causes:

Rhinitis/rhinosinusitis (post-nasal drip)

Pharyngitis

Tonsillitis

Pneumonia

Bronchitis

Bronchiectasis

Pulmonary TB

Malignant tumour - lung cancer, secondary spread of cancers to lung.

Benign tumour - lipoma, carcinoid.

Asthma

Chronic bronchitis

Bronchiolitis

Interstitial lung disorders

Foreign body inhalation

Drugs - ACE inhibitors

Gastro-oesophageal reflux disease

Congestive heart failure

Functional (psychogenic cough)