What is asthma?

Asthma is a medical condition that affects the airways (the breathing tubes that carry air into our lungs). From time to time, people with asthma find it harder to breathe in and out, because the airways in their lungs become narrower – like trying to breathe through a thin straw. 

At other times their breathing is normal.

There is no cure for asthma, but it can usually be well controlled. Most people with asthma can stay active and have a healthy life.

For good control of asthma, you need:

  • medicines – taken the right way, at the right time
  • regular medical visits for check-ups and to learn more about living with asthma
  • an action plan, so you know exactly what to do when symptoms happen.

What are the symptoms of asthma?

The most common symptoms of asthma are:

  • wheezing – a high-pitched sound coming from the chest while breathing
  • a feeling of not being able to get enough air or being short of breath
  • a feeling of tightness in the chest
  • coughing.

You don’t have to have all these symptoms to have asthma. 

Asthma symptoms can be triggered by different things for different people. Common triggers include exercise, cigarette smoke, colds and flu, and allergens in the air (e.g. grass pollen).

What is happening inside the lungs when someone has asthma symptoms?

Airways tighten up.
Inside the wall of each airway there is a thin layer of muscle. When it contracts, it makes the airway narrower – reliever medicines work by relaxing these muscles in the airways.

Airways thicken up.
The lining of the tubes gets swollen and inflamed, leaving less space to breathe through – preventer medicines work by reducing the inflammation that causes the swelling.

Airways fill up.
The inside of the tubes can get blocked by mucus – preventer medicines reduce mucus. 

All these can happen at the same time.

15 Asthma Schematic

Who gets asthma?

Almost 2.8 million or 10.8% of Australians have asthma, including children and adults. Asthma is more common in families with asthma or allergies, but not everyone with asthma has allergies. Asthma is common in children, but it can also start later.

Asthma often starts as wheezing at preschool age. Not all wheezing is asthma – many preschool children who wheeze do not have asthma by primary school age.

Adults of any age can develop asthma, even if they did not have asthma as a child.

What causes asthma?

The exact causes of asthma are not known. The risk of getting asthma partly depends on genetics. Asthma can run in families.

Asthma can be allergic or non-allergic. Allergic asthma is more common in families with asthma and allergies.

Children’s risk of getting asthma seems to be increased by mothers smoking while pregnant, people smoking around babies or young children, air pollution from traffic or industry, mouldy houses, and being born premature or with a low birth weight.

Adults can develop asthma over  time  from indoor air pollution at work or home (for example, by breathing fumes that irritate the lungs, or breathing in dusts that they are allergic to).

Athletes can develop asthma after very intensive training over several years, especially while breathing air that is polluted, cold or dry.

Researchers have found many other things that could help explain why asthma is so common, but we don’t yet know exactly why some people get asthma and others don’t.

What is an asthma flare up?

An asthma flare-up is when asthma symptoms start up or get worse compared to usual. The symptoms won’t go away by themselves and need treatment.

These flare-ups can happen quite quickly (e.g. if you are exposed to smoke) but they can also come on gradually over hours or days (e.g. if you get a cold).

The term ‘asthma attack’ is confusing because it means different things to different people – from a bout of wheezing after running for the bus through to being admitted to hospital for asthma.

An asthma flare-up can become serious if not treated properly, even in someone whose asthma is usually mild or well controlled. A severe flare-up needs urgent treatment by a doctor or hospital emergency department.

Related Resources

My Asthma Guide 2022
My Asthma Guide

My Asthma Guide is a handbook designed to help patients understand and manage their asthma.

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