What are asthma triggers?

Common asthma triggers

Asthma triggers can cause the airways to become narrow and inflamed, leading to asthma symptoms.

Avoiding triggers, if possible, can help to control asthma. Anything that causes a reaction can set off your asthma symptoms.

These triggers differ between individuals. Over time, you will get to know which circumstances can make your asthma get worse. Some can be avoided altogether while others you will need to plan for.

Colds, flu and other respiratory infections

Colds and flu can hit hard if you have asthma. In fact, the common cold is behind around 4 out of 5 bad asthma attacks. Check out our Asthma winter checklist for great tips on how to avoid these types of triggers.

Cigarette smoke

People with asthma have even more reason to avoid smoking than those without asthma. Sensitive, asthmatic lungs are especially vulnerable to the damaging effects of cigarette smoke. Read more in our Smoking triggers my asthma and allergies fact sheet.

Allergy related triggers

One in five Australians have allergies, including most people with asthma. Allergies tend to run in families, but family members may not have the same response.

Allergies occur when a person’s immune system reacts to substances (allergens) that are harmless to most people. These allergens include house dust mites, mould, pollen and pets.

Exercise

Exercise is another common trigger, but is great for health and well-being, and having asthma shouldn't stop you playing sport or taking part in any other activity. Your symptoms can usually be managed by warming up properly and taking some extra asthma medication before you begin. Read more in our Exercise and asthma fact sheet.

Other triggers

There are a number of other triggers that many affect individuals at various times. These include:

• weather e.g. cold air, change in temperature, thunderstorms
• work-related triggers e.g. wood dust, chemicals, metal salts
• irritating substances breathed in the air, such as bushfire smoke
• certain medicines, e.g. aspirin, some blood pressure drugs
• stress and high emotions, such as crying.

What are my triggers?

Most people are allergic to more than one trigger and sometimes the response is different, so you could get itchy eyes around cats but a runny nose during pollen season. The severity of the allergic reaction varies between people and depends on the circumstances. A reaction may not be immediate.

Sometimes it can be fairly obvious what triggers your asthma. If you have symptoms after coming in contact with cats or dogs (the most common causes of pet allergies) then pets are probably one of your triggers. The same applies for contact with smoke from cigarettes or open fires. 

Triggers like pollen can be more difficult to determine because the allergens are not visible. It is important to keep a diary of when you experience symptoms and note where you were at the time, what the weather conditions were like and what things you were exposed to including stress.

Can I avoid triggers?

It is not always possible to avoid your triggers however reducing exposure to your asthma or allergy triggers may make your symptoms easier to manage.

The first step is to know your triggers so you can focus your efforts in the right area. Your doctor will be able to help you work this out and give you some helpful advice and tips on how to avoid your triggers.

More information

Find more information on managing your asthma and triggers by accessing our fact sheets and by visiting the National Asthma Council's Sensitive Choice website.