A cough is a sudden, noisy expulsion of air from the lungs that sometimes includes mucous.
What is going on in the body?
Coughing is usually a reflex response of the body caused by an irritation in the throat or windpipe. A reflex response means that the body does something automatically, without a person thinking about it. This reflex helps to protect the lungs from bacteria, viruses, dust, and other damaging substances. However, people can cough on purpose if they want or need to. There are many possible causes of a cough, ranging from allergies to lung infections and cancer.
What are the signs and symptoms of the condition?
When a person has a cough, there are many things a doctor may want to know, such as:
Other symptoms may also be asked about, such as whether the person has a fever, heartburn, runny nose, or weight loss.
- when the cough started and how long it has been going on
- if the cough is constant or only occasional
- if the cough is dry or brings up any mucous or phlegm; if so, the colour of the phlegm may be important
- if anyone else the person knows has been coughing or sick
- whether the cough seems to be related to a certain time of year, which often happens when people have seasonal allergies
- whether or not any blood has been coughed up
What are the causes and risks of the condition?
There are a number of conditions that can cause a cough, including:
- lung or throat infections, such as a sore throat, acute bronchitis, or pneumonia
- gastro-oesophageal reflux, or heartburn
- exposure to certain chemicals or gases, such as car exhaust
- chronic obstructive pulmonary disease (COPD), such as emphysema
- tumours or cancer, including lung cancer
- congestive heart failure, which can cause fluid build up in the lungs and make a person cough
- ACE inhibitors, which are drugs that are often used to treat high blood pressure
- a foreign body in the windpipe, which can happen when small children put objects in their mouths
- miscellaneous conditions, such as Tourette syndrome
Other causes are also possible. Sometimes no cause can be found for a person's coughing.
What can be done to prevent the condition?
Preventing a cough depends on what is causing it. Not smoking, for example, can prevent a "smoker's cough." Early treatment of gastro-oesophageal reflux and congestive heart failure can prevent coughing from these conditions. Many cases of coughing cannot be prevented, but they can be treated.
How is the condition diagnosed?
The role of the doctor is to help a person figure out why he or she is coughing. The doctor will start with a history and physical examination. This may be all that is needed to diagnose the cause.
Other tests may be done as well. These include blood tests and x-rays of the chest. Lung function tests can help to diagnose asthma or emphysema
What are the long-term effects of the condition?
A cough that is severe can be annoying and prevent sleep and other activities. Most long-term effects are related to the underlying cause. For example, those who have lung cancer as the cause of their cough may die. Those who have bronchitis usually get better within a few weeks and have no long-term effects at all.
What are the risks to others?
If the cause of a cough is a bacterial or viral infection, the person can spread these germs to others by coughing.
What are the treatments for the condition?
The underlying cause of the cough should be treated if possible. Drugs such as dextromethorphan or codeine can be used to suppress a cough. Persons with a tumour or cancer may need surgery, radiation therapy, or chemotherapy. Those who have with a lung infection may need antibiotics. Persons with asthma or emphysema may need medications to reduce the inflammation in the lungs and to help open the airways. Persons taking ACE inhibitors for high blood pressure may need to switch to a different type of medication.
What are the side effects of the treatments?
Side effects vary depending on the treatment. All medications have possible side effects, including allergic reactions, stomach upset, and headache. For example, codeine may cause a person to become drowsy or nauseous. Specific side effects depend on the drugs used. All surgery carries a risk of bleeding, infection, and reaction to any analgesics used.
What happens after treatment for the condition?
What happens after treatment depends on the underlying cause of the cough. For example, a person with asthma or emphysema may need treatment for life. Persons with acute bronchitis may need no further treatment or monitoring after they recover.
How is the condition monitored?
People can monitor their cough and how it is responding to treatment. More specific monitoring depends on the underlying cause of the cough
Reviewer: eknowhow Medical Review Panel
Editor: Dr John Hearne
Last Updated: 16/09/2004
Potential conflict of interest information for reviewers available on request