Everyone gets a cough from time to time. Coughing is the body’s natural response to an irritant in the airways. We cough when smoke or fine particles get into the throat or airways. A cough is a common symptom of hayfever and asthma. The common cold and other upper respiratory infections also cause coughing.
It’s not unusual for a viral infection of the upper airways to cause a cough that lingers for weeks.
So, what exactly is a chronic cough?
Generally, most doctors describe a cough as chronic if it has lasted more than 8 weeks after a cold or other cause, or has arisen without an obvious cause.
Many things can cause a chronic cough so this is a symptom that often needs in depth investigation by an expert.
Dr Gareth Roberts is a General Respiratory Consultant who specialises in assessing people with a chronic cough to discover the underlying cause and to treat it.
In your initial consultation, Dr Roberts will take a detailed medical history, ask you lots of questions and then set up some tests to find out the cause of your cough. This may mean ruling out one cause after another.
What other symptoms do you have?
This is one of the first questions that Dr Roberts will ask you. Have you any of these other symptoms in addition to your cough?
- The need to clear your throat often
- Frequent attacks of heartburn or burping up acid
- A blocked nose or a runny nose
- A post nasal drip – fluid from your nose running down the back of your throat
- A sore throat or a hoarse voice
- Coughing up blood or blood-stained sputum
- Severe anxiety or stress
How is the cough affecting you?
- Is it a minor irritant or is it affecting your work and home life?
- Do you have bouts of severe coughing during which you bring up blood?
- Does your cough mean that you can’t sleep properly at night?
Possible causes of chronic cough
These problems are common causes of chronic cough:
- Asthma – this may be undiagnosed
- Gastro-oesophageal reflux disease (GORD or GERD) – a weakness in the top of the stomach allows acid back up into the oesophagus and throat, where it can damage the top of the windpipe, irritating the tissues and causing a cough.
- Post-nasal drip – commonly due to problems within the sinuses
- Viral infection or other infections of the airways
- Side effects of medicines, such as those taken to control blood pressure
- Smoking related changes in the lungs – many long-term smokers develop chronic bronchitis
Less common causes of chronic cough include:
- A foreign body in the airways – more likely in children than in adults
- Chronic obstructive pulmonary disease (COPD) – a progressive lung disease that occurs when the delicate tissues are replaced by scar tissue. The most common cause is many years of smoking.
- Cystic fibrosis – a genetic disease that causes mucus to build up in the lungs. People with CF have physiotherapy to clear this but they are prone to more upper respiratory infections and symptoms.
- Bronchiectasis – a widening of some of the smaller airways causes mucus to build up, increasing the risk of inflammation and infection. The irritation leads to the cough. This is important to diagnose as patients often require longer courses of antibiotics to treat infection.
- Lung cancer – this type of cancer tends not to show symptoms in the early stages but diagnosis and treatments are improving all the time.
- Sarcoidosis – a disease that causes inflammation in the lungs and skin.
When to seek medical advice
If you have a cough for more than 8 weeks you should get it checked out.
Although a chronic cough can be a symptom of lung cancer, particularly if you bring up blood when you cough, it is a relatively rare cause.
Many people put off seeing their doctor, which is a bad idea in either case.
- If it is lung cancer, the earlier the treatment starts the better,
- If the problem is caused by something else, you are delaying treatment that could rid you of the cough.
NHS Choices has more detailed information on chronic cough.