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Probability diagnosis

Upper respiratory infection

Postnasal drip/sinusitis/rhinitis


Inhaled irritants

Acute bronchitis

Chronic bronchitis/COPD

Serious disorders not to be missed


  • left ventricular failure


  • lung cancer

  • larynx


  • tuberculosis

  • pneumonia

  • influenza

  • lung abscess

  • HIV infection

  • SARS (coronavirus)


  • asthma

  • cystic fibrosis

  • foreign body

  • pneumothorax

Pitfalls (often missed)

Atypical pneumonias

Gastro-oesophageal reflux (nocturnal)

Smoking (children/adolescents)


Whooping cough (pertussis)

Interstitial lung disorders (e.g. idiopathic pulmonary fibrosis)


Masquerades checklist

Drugs (e.g. ACE inhibitors, beta blockers, inhaled steroids, sulfasalazine)

Is the patient trying to tell me something?

Anxiety and habit.

Key history

Determine the nature of the cough, especially associated symptoms such as the nature of the sputum, breathlessness, wheezing and constitutional symptoms. Haemoptysis See ‘Haemoptysis (in adults)’. History of smoking habits, past and present, and occupational history are essential. Past history, especially respiratory and drug intake.

Key examination

  • General examination including a search for enlarged cervical or axillary glands

  • Careful examination of the lungs and cardiovascular system with inspection of sputum

Key investigations

More applicable if haemoptysis


  • Sputum cytology and culture

  • Respiratory function tests

  • Plain CXR and others as appropriate

Diagnostic tips

  • Postnasal drip is the commonest cause of a persistent or chronic cough especially at night.

  • Cough may persist for many weeks following a URTI.

  • Cough is the cardinal feature of chronic bronchitis.

  • Unexplained cough >50 years is bronchial carcinoma until proved otherwise (esp. if a history of smoking).

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