Asthma overview

About one in 9 Australians has asthma - a chronic (ongoing) condition that affects the airways in the lungs. Asthma affects both children and adults. People with asthma have inflamed airways that are highly sensitive, and when exposed to certain triggers, their over-sensitive airways narrow, or constrict, making breathing difficult.

While there is no cure, most people with asthma are able to control their symptoms by avoiding their triggers and taking medicines. Asthma can be life-threatening in some people, so it’s important to work with your doctor to monitor and control your asthma as much as possible.


The typical symptoms of asthma include:

  • breathlessness;
  • wheezing (a whistling sound in the chest);
  • chest tightness; and
  • cough.

Most people with mild asthma feel well most of the time and their symptoms are easily controlled with treatment. They may experience symptoms from time to time when they have episodes of airway narrowing, usually after exposure to one or more triggers. People with severe asthma have regular or persistent symptoms that are more difficult to control with treatment.

What causes asthma?

The exact cause of asthma is not known. What is known is that lots of factors contribute to its development — for example, a family history of asthma, or a personal or family history of allergic conditions such as eczema or allergic rhinitis (hay fever). Exposure to tobacco smoke (especially early in life) can increase your risk of developing asthma.

How asthma affects your airways

Airway narrowing in asthma makes breathing difficult by reducing airflow - the amount of air that can travel in and out of the lungs. The narrowing comes and goes, and is due to:

  • inflammation and swelling of the airways;
  • excessive production of thick mucus in the airways; and
  • tightening of the bands of smooth muscle around the airways (known as bronchoconstriction).

narrowing of airways during asthma attack

What can trigger asthma symptoms?

Many things can trigger asthma symptoms, and asthma triggers vary from person to person.

For many people with asthma, it is an allergy that brings on (‘triggers’) their asthma symptoms. Other triggers include vigorous exercise (exercise-induced asthma) or having a cold. In fact, colds and flu are the most common triggers of asthma attacks. These viral infections can aggravate your airways, nose, sinuses, throat and lungs, causing a flare-up.

Thunderstorm asthma is asthma that is triggered by the combined effects of weather conditions, pollens and other airborne allergens.

The table below shows some common asthma triggers — those that are allergens (substances that provoke an allergic reaction) are on the left, and those that can trigger asthma symptoms but do not involve an allergic reaction are on the right.

Common asthma triggers
(substances that produce an allergic reaction)
Other triggers
  • Dust mites and their droppings
  • Pollens (usually from grasses, trees or weeds, rather than flowers)
  • Animal or bird allergens: dander (skin scales or flakes from hair or feathers); saliva or urine
  • Moulds
  • Cockroach allergen (cockroach droppings found in the dust of houses where cockroaches are present)
  • Occupational allergens (e.g. sawdusts, flour and latex)
  • Viral respiratory infections (colds and flu)
  • Some medicines, such as aspirin and non-steroidal anti-inflammatory drugs (NSAIDs)
  • Air pollution (including cigarette smoke)
  • Exercise
  • Emotions and emotional reactions such as stress, anxiety, hearty laughing or crying
  • Heartburn (reflux)
  • Cold air and ambient temperature changes
  • Some food additives (sulphur dioxide is the food additive thought most likely to trigger asthma)

Tests and diagnosis

Your doctor will ask questions about your symptoms and perform a physical examination. Your doctor may suggest you do lung function (breathing) tests, such as peak flow tests and spirometry. (To do lung function tests, you need to be able to follow instructions, so children usually need to be older than about 6 years of age to be tested.)

Peak flow tests use a peak flow meter to measure the speed of airflow out of the lungs. A spirometer can measure the total amount of air you can breathe out after taking a deep breath in (forced vital capacity - FVC), and how much air you can blow out in one second (forced expiratory volume in one second - FEV1). Lung function tests can also test the effect of asthma medicines on your breathing.

To diagnose asthma, your doctor will want to confirm that your symptoms come and go. In addition, the lung function tests should show variation in lung function. In other words, airflow is limited some, but not all, of the time due to airway narrowing. If symptoms and lung function are improved with asthma medicines, that can help to confirm the diagnosis.

Asthma treatments

If you or your child has asthma you can help control symptoms and prevent asthma attacks by:

  • monitoring your symptoms and airflow (peak expiratory flow);
  • taking medicines; and
  • avoiding or controlling the triggers that set off your asthma.

It’s important to work with your doctor to create a written individual asthma action plan to help you achieve good asthma control and manage asthma flare-ups as soon as they happen. Asthma action plans help you recognise if your asthma is getting worse and tell you what to do about it.

Your plan should be readily available - you can upload it to a asthma management app or print several copies of the plan. If your child has asthma you should provide their school, day care and other carers with a copy of the plan.

Monitoring asthma

Monitoring your symptoms and airflow helps you recognise when your asthma is well controlled and when it isn’t. You should be aware of the symptoms and signs of worsening asthma, such as needing to use your reliever medicine more frequently. Regularly monitoring your lung function with a peak flow meter also helps you identify changes in your asthma or flare-ups early.

It’s a good idea to record your symptoms and peak flow scores in a diary. Alternatively, the National Asthma Council Australia has a mobile only website (similar to a phone app) for asthma management called ‘Asthma Buddy’.

If your peak flow measurements are lower than normal or your symptoms are worse, you should check your asthma action plan. You may need to adjust your medicines and see your doctor.


Medicines for asthma are often described as relievers and preventers. Most regular asthma medicines are delivered by an inhaler device (often called a puffer), although some are available in tablet form. There are also some medicines — used in specific circumstances, such as treating asthma flare-ups — that are given via injection.

Relievers: these medicines are known as bronchodilators because they help to open up the airways, helping you to breathe more easily when you're having difficulty. Unless advised otherwise by your doctor, relievers should be used on an ‘as-needed’ basis for the relief of asthma symptoms.

Preventers: these work by reducing the underlying inflammation of the airways, helping to reduce the likelihood and severity of asthma flare-ups. Unlike reliever medicines, you should take your preventer every day, as prescribed by your doctor, to help keep your asthma under control.

Some asthma products contain a combination of a preventer and a reliever to help keep asthma under control.

Make sure you visit your doctor regularly for check-ups to ensure that you are taking the correct medicines for your asthma, and using your inhaler correctly.

Controlling or avoiding asthma triggers

Remember, different people have different triggers, so knowing what triggers your asthma is an important first step. By avoiding your triggers, you can reduce asthma flare-ups.

It’s important for people with asthma to avoid tobacco smoke (including smoking and passive smoking). Avoid any medicines, foods and food additives that are triggers, and try to avoid allergens as much as you can. Allergy testing and treatment with immunotherapy may be recommended for some people.

Talk to your doctor if exercise triggers your asthma - there are steps you can take to manage this situation.

Colds and flu

Colds and flu are among the most common triggers for asthma. While it’s impossible to avoid all infections, getting a flu vaccination each year greatly reduces your chances of catching influenza (the flu). The best time to be vaccinated is in autumn, before the start of flu season.

Influenza vaccination is recommended for all people older than 6 months who want to avoid the flu and its complications. It is strongly recommended (and available for free) for children and adults in Australia with severe asthma. Ask your doctor whether you are eligible for free influenza vaccination under the National Immunisation Program Schedule.

Frequent hand washing with soap and water can also help stop the spread of cold and flu germs, and may help you avoid getting sick.

Complementary therapies

There is currently insufficient evidence from clinical trials to support the use of most complementary therapies in the treatment of asthma. The National Asthma Council Australia recommends that the use of complementary therapies should not take the place of conventional treatments for asthma.

Also, complementary medicines can cause side effects, and some products can cause serious allergic reactions. Make sure you discuss the safety of any complementary or alternative treatments, including changes to your diet, with your doctor before you try them.


1. National Asthma Council Australia. Australian Asthma Handbook, Version 1.2. National Asthma Council Australia, Melbourne, 2016. Website. Available from: (accessed Nov 2017).
2. National Asthma Council Australia. Australian Asthma Handbook - Quick Reference Guide, Version 1.2. National Asthma Council Australia, Melbourne, 2016. Available from: (accessed Nov 2017).
3. Australian Institute of Health and Welfare (AIHW). Asthma web report, 22 Dec 2016. (accessed Nov 2017).
4. National Asthma Council Australia. New mobile Asthma Buddy to help Australians better manage their asthma (31 Oct 2017). (accessed Nov 2017).