Cough is a common symptom, which in most cases is self limiting. It is usually a normal body response to either an infection or irritation of the vocal cords and / or upper airways and almost always goes away by itself after a few days.
Occasionally a cough might persist or become so severe as to interfere with normal functioning. Rarely, the development of a cough is a signal that something more serious might be present.
The most common causes of a persistent cough are listed below:
Following an infection
Due to rhinosinusitis (inflammation of nose and / or sinuses)
Asthma (in these situations the cough is often but NOT ALWAYS accompanied by a wheeze)
Gastro-oesophageal reflux disease (indigestion, heart burn)
Vocal cord irritation which may be due to any of the conditions above
Less common causes of cough include:
Anyone who has had a cough for a few weeks or who has a severe cough that is interfering with their lives should have a chest x-ray to ensure that a serious disease is not present. Anyone who coughs up blood should see their doctor urgently.
If a cough persists even if the chest x-ray is normal, then it may be appropriate to seek referral to a respiratory physician (specialist in lung diseases). The respiratory physician is likely to organise some tests including tests looking at your lung function, tests whether asthma or reflux disease is present and occasionally more involved testing such as a CT scan or bronchoscopy (where a small tube with a camera on it is passed into the airways under sedation) is required.
All causes of cough are treatable and the treatment depends on what cause is found.