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Symptom sorter - cough in adults

GPs Dr Keith Hopcroft and Dr Vincent Forte begin their series on understanding common symptoms with a look at cough in adults.

The GP overview

This is a symptom that patients seem to fear or value – as a signifier of possible cancer or a justifier of antibiotics – far more than GPs. Most coughs are simply viral URTIs, but the GP should be aware of the various other possibilities, especially when the symptom is persistent.

Differential diagnosis


  • URTI.
  • LRTI.
  • Asthma.
  • COPD.
  • ACE inhibitor side-effect.


  • Smoking (including passive smoking).
  • Lung tumour (primary or secondary).
  • Rhinitis.
  • GORD.
  • Left ventricular failure.
  • Bronchiectasis.
  • Aspiration (for example, post stroke).


  • Tuberculosis.
  • Other medication side-effect (such as methotrexate).
  • Pulmonary fibrosis.
  • Fibrosing alveolitis.
  • Extrinsic allergic alveolitis.
  • Psychogenic.
  • Laryngeal carcinoma.
  • Inhaled foreign body.
  • Diaphragmatic irritation (for example, abscess).

Ready reckoner

 URTILRTIAsthmaCOPDACE inhibitor side-effect
Associated shortness of breathNoPossiblePossibleYesNo
Productive coughPossibleYesPossibleYesNo
Persistent or recurrent coughNoNoYesYesYes
Audible wheezeNoPossiblePossiblePossibleNo
On ACE inhibitorPossiblePossiblePossiblePossibleYes

Possible investigations




FBC, ESR/CRP, spirometry, PEFR

Small print

  • Sputum, cardiac investigations, serum precipitins, hospital-based investigations such as CT scan and bronchoscopy.
  • FBC – haemoglobin may be reduced in malignancy and chronic illness, WCC raised in infections, eosinophils raised in allergic conditions.
  • ESR/CRP – raised in neoplasia, infective and inflammatory conditions.
  • Chest X-ray – may show signs in a variety of the relevant differentials, such as LRTI, tumour and TB.
  • Spirometry – may show characteristic patterns particularly in asthma, COPD and pulmonary fibrosis.
  • Serial peak flow – may be helpful in diagnosis of asthma.
  • Sputum – may be useful in diagnosing TB and occasionally helps guide antibiotic treatment in LRTI or exacerbation of COPD.
  • Cardiac investigations, such as BNP or echocardiogram if LVF suspected.
  • Serum precipitins in suspected extrinsic allergic alveolitis.
  • Hospital-based investigations – further investigations such as CT scan or bronchoscopy may be required to clarify CXR abnormalities or pursue clinical suspicion.

Top tips

  • Explain to patients that it is not unusual for the cough of a simple URTI to go on for three weeks – this will reduce unnecessary re-attendances.
  • Take a careful history of provoking factors in the case of persistent cough – this is more likely to reveal the diagnosis than is chest auscultation.
  • Have a low threshold for arranging a chest X-ray in the middle-aged and elderly smoker with a cough.
  • ACE inhibitor-associated cough may come on many months – or even longer – after initiating treatment. It starts to improve within one to four weeks of stopping treatment, but may take three months to settle completely.
  • In a persistent cough with a normal CXR and no chest signs, think asthma, GORD and rhinitis – a therapeutic trial for each may be needed to clinch the diagnosis.

Red flags

  • Remember to ask about foreign travel. Atypical pneumonias are infrequent, and TB rare, but both can still present.
  • Beware of persistent cough, weight loss and voice change in a smoker – arrange an X-ray to exclude malignancy.
  • Night sweats with persistent cough suggest significant pathology such as TB or malignancy.
  • Beware the patient on immunosuppressants: these drugs may alter the clinical picture, predispose to serious complications and in some cases (e.g. methotrexate) may be the cause of the cough itself.

Dr Keith Hopcroft is a GP in Laindon, Essex.

Dr Vincent Forte is a GP in Gorleston, Norfolk.

The fifth edition of Symptom Sorter is available from Radcliffe Publishing for £34.99.

Symptom Sorter 5th edition

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Readers' comments (8)

  • LPR?

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  • No mention of whooping cough in adults - paroxysmal cough lasting 100 days - whooping cough

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  • Thanks both
    LPR I guess we assumed was incorporated in GORD, but we could make that more explicit.
    I agree pertussis is worth a thought. It's highlighted in the childhood cough section but agree it merits a mention here - we'll incorporate it in the next edition!

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  • sarcoidosis is probably worth mentioning separately from the other granulomatous conditions like tb

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  • Excellent article. Please include pertussis

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  • Good article. Informative & helpful.

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  • Good article. Could also mention thrombocytosis in FBC section as increasing likelihood of malignancy as per CAPER

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  • good and instructive

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