Cold & flu health centre

Adult chest infections

Anyone can have a chest infection, and they are common after having a cold or flu, especially in the autumn and winter.

The two main types of chest infection in adults are acute bronchitis and pneumonia.

A chest infection is often mild and will clear up on its own, but in some adults it may be serious enough to require urgent medical treatment.

What is a chest infection?

A chest infection refers to an infection that occurs in the airways or the lungs.

The airways are a series of tubes that gradually get smaller and more numerous to deliver oxygen taken in through your nose or mouth to your lungs. The largest tube is the trachea, or windpipe, in your neck. This single tube splits into two tubes – one for each lung – known as the primary bronchi. These, in turn, branch out into smaller bronchi with tiny air sacs called alveoli at the end.

When you breathe in, you breathe in oxygen that is delivered to the lungs. However, if the oxygen you breathe in is also carrying tiny droplets of a virus or bacteria after someone has sneezed, or if they enter your nose after you touch a contaminated surface and then an area near your nose, you may develop an infection that can settle into the airways or lungs.

Acute bronchitis is an infection of the large bronchial tubes and is usually, but not always, caused by a virus. Pneumonia is an infection of the lungs in which the tiny sacs become filled with fluid, and is most often, but not always, caused by a bacterial infection.

Unlike acute bronchitis, which is a temporary condition, chronic bronchitis, or chronic obstructive pulmonary disease (COPD), is not linked to an infection, but is caused by an irritant such as smoking or household chemicals and is a long-term condition.

Who is more at risk of developing a chest infection?

Although anyone can develop a chest infection, having a weakened immune system puts a person more at risk. This is why a chest infection often occurs after having a cold or flu, when your immune system is temporarily weakened after fighting off the virus.

The symptoms and complications of a chest infection can be much worse in people with certain medical conditions.

Adults who are more at risk if they have a chest infection include:

• People who are 65 years old and older
• People who smoke or drink alcohol excessively
• People with chronic respiratory problems, such as asthma
• People who are very overweight
• Pregnant women
• Adults with diabetes and other long-term health conditions, such as heart, kidney or liver disease
• People with cancer or with HIV or AIDS
• People who use medication that can suppress their immune system