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Chest infections are usually caused by either bacteria or viruses.

Chest infections are usually caused by either bacteria or viruses.
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Chest infection

4-minute read

What is a chest infection?

A chest infection is an infection of the lungs.

If the infection is in the smaller air sacs of the lungs — known as the alveoli — it is called pneumonia. If it is in the larger airways — known as the bronchi — it is called bronchitis. The airways become swollen and make more mucus or pus which blocks the airways and makes it hard to breathe.

Chest infections can be spread to others when an infected person coughs or sneezes.

They are more common in:

  • babies and young children
  • pregnant women
  • elderly people
  • smokers
  • people with long-term health conditions or weakened immune systems

What are the symptoms of a chest infection?

The most common symptoms of a chest infection are:

CHECK YOUR SYMPTOMS — Use our Symptom Checker and find out if you need to seek medical help.

When should I see my doctor?

You should see a doctor straight away, or go to a hospital emergency department, if:

  • you are short of breath
  • it hurts to breathe
  • you have a very high fever
  • you are coughing up a lot of phlegm
  • there is blood in the phlegm
  • your symptoms are not improving or they are getting worse
  • you have a heart or lung disease, such as heart failure or asthma

What causes chest infections?

Chest infections are usually caused by either bacteria or viruses. Pneumonia is often caused by bacteria, and bronchitis is often caused by viruses. Occasionally, chest infections can be caused by fungi.

How are chest infections diagnosed?

Your doctor will take your medical history, listen to your breathing, and may order blood tests, a test of your phlegm, or a chest x-ray. They might also do a lung function test or take a swab to work out the cause of your infection

How are chest infections treated?

Often chest infections do not need any medical treatment. But in some cases, antibiotics are needed. Only bacterial infections respond to treatment with antibiotics — they will not help viral infections. If you are prescribed antibiotics you must take the full course even if you feel better after 2 to 3 days.

Pneumonia can be life threatening for some people. Babies, young children and older adults may need to be looked after in hospital if they have pneumonia.

If you have a chest infection, you can look after yourself by:

Inhaling steam and raising your head with a pillow in bed can help to ease the symptoms. You can also talk to your pharmacist about whether a decongestant medicine might help.

Can chest infections be prevented?

You can reduce the risk of getting a chest infection, or of passing one on, by:

  • washing your hands with soapy water after coughing, sneezing and using tissues
  • covering your mouth when you cough or sneeze, and dispose of used tissues in the rubbish bin straight away
  • not attending work, school or day care while feeling unwell
  • quitting smoking if you smoke
  • limiting alcohol
  • eating healthy food

Your doctor may recommend vaccination against the flu (influenza) or pneumococcal infections, particularly for babies, elderly people, pregnant women or people with long-term health conditions.

If you think you are at high risk of chest infections, talk to your doctor.

Resources and support

If you need to know more about chest infections, or to get advice, call healthdirect on 1800 022 222 to speak with a registered nurse, 24 hours, 7 days (known as NURSE-ON-CALL in Victoria).

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: March 2021

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