Asthma

Asthma is a common inflammatory disease of the airways.

Normally the airways are open and relaxed, allowing air to easily move in and out. People with asthma have sensitive airways that are primed to react to triggers in the environment, leading to an asthma attack.

The triggers that bring on an asthma attack vary between different people. Asthma is often triggered by the immune system responding to inhaled substances such as pollen, house dust mites and mould spores. Asthma attacks can also be triggered by the common cold, exercising, or by environmental irritants like cigarette smoke and pollution.

During an asthma attack, the airway lining becomes swollen, inflamed and thick with mucous. The muscles in the airways tighten, narrowing the airways. These changes restrict airflow, making it difficult to breathe.

Asthma attacks can come on gradually or quickly. When asthma occurs as an acute attack, the airflow restriction can be life threatening. Each year approximately 400 people in Australia die from asthma.

Most people with asthma only show symptoms when they are exposed to their trigger, bringing on an asthma attack. Symptoms of asthma include:

• tight chest
• shortness of breath
• wheezing
• coughing

Symptoms are often worse during exercise, at night or in the early morning when the weather is cool.

The precise cause of asthma is unknown. Factors that are associated with an increased risk of asthma include:

• family history of asthma, eczema, hay fever or other allergies
• exposure to tobacco smoke, especially as a baby or young child
• exposure to environmental hazards
• obesity
• sedentary lifestyle

In adults, asthma is two times more prevalent and more severe in women than men, despite being more common in boys than girls before puberty.

Indigenous Australians are nearly twice as likely to have asthma compared with non-Indigenous Australians.

Thunderstorm asthma is a form of asthma triggered by grass pollen released into the air during some thunderstorms. In these conditions large numbers of people may suffer severe asthma attacks, even if they have never had asthma before.

The frequency of thunderstorm asthma events is predicted to increase, but the risk factors are poorly understood. Our researchers are investigating the environmental and patient factors that put people at risk of thunderstorm asthma. This work will lead to better warning systems and urban planning advice to keep people safe from thunderstorm asthma.

There is no cure for asthma but with appropriate therapy the disease can be well controlled. Common medications include:

• relievers: drugs that give rapid relief of symptoms during an asthma attack by opening up the airways to make breathing easier
• preventers: drugs, usually anti-inflammatory steroids, taken every day to reduce the likelihood of asthma attacks. These drugs reduce the redness and swelling in the airways and help to dry up the mucous
• combination preventers: drugs combining a long-acting airway relaxer and an anti-inflammatory steroid preventer, which work together to help control asthma symptoms
• severe asthma treatments: an injectable treatment given every 2-4 weeks for people with severe disease that is not controlled by maximal preventer therapy.

Alongside these medications, people with asthma should ask their medical practitioner to write an Asthma Action Plan that explains how to manage their condition and what to do during an asthma attack.

For more detailed information on asthma treatment, visit Asthma Australia or the National Asthma Council of Australia.