Updated 21 February 2018

How is a chronic cough diagnosed?

Any cough lasting longer than 8 weeks warrants investigation, particularly if you have any of the warning signs.


A very detailed medical history and physical examination will frequently suffice to determine the major factors that contribute to a chronic cough.

Often, the trigger factors are identifiable without any further testing, and treatment will lead to a successful outcome without doing anything more.

Your doctor is likely to ask whether you smoke, use ACE inhibitors for hypertension and/or whether you’ve had a recent infection (e.g. the common cold).

Frequently, the associated symptoms (or lack thereof) and physical findings provide an answer in terms of the cause. 

In specific situations, such as suspected asthma, cancer or acid reflux, further specialised tests may be needed.

Examples include:

• Lung function testing
• Chest X-ray with or without a computerised tomography (CT) scan
• Gastroscopy 
• Oeshophageal pH monitoring
• Lab tests on a sample of mucus

Reviewed by Professor Richard van Zyl-Smit, Head of the Lung Clinical Research Unit at the University of Cape Town. MBChB, MRCP(UK), Dip HIV(Man), MMED, FCP(SA), Cert Pulm(SA), PhD.



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Professor Keertan Dheda has received several prestigious awards including the 2014 Oppenheimer Award, and has published over 160 peer-reviewed papers and holds 3 patents related to new TB diagnostic or infection control technologies. He serves on the editorial board of the journals PLoS One, the International Journal of Tuberculosis and Lung Disease, American Journal of Respiratory and Critical Medicine, Lancet Respiratory Diseases and Nature Scientific Reports, amongst others. Read his full biography at the University of Cape Town Lung Institute.

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