Understanding asthma triggers

If you have asthma, you're more likely to react to triggers because your airways are more sensitive

Knowing what your asthma triggers are and how to deal with them means you’re more likely to stay well with your asthma.

What’s an asthma trigger?

An asthma trigger is anything that can set off your asthma by irritating your sensitive airways even more. You may find, for example, that being around cats or dust sets your symptoms off. Or it might be pollen, cold weather, or being near someone who’s smoking.

How many asthma triggers can you have?

You can have one or more asthma triggers. What sets off your asthma symptoms may be different to what sets off someone else’s. Everyone with asthma has their own personal mix of triggers.

Why do asthma triggers sometimes not cause symptoms?

The sensitivity of your airways can vary day to day, month to month, year to year. If your asthma’s well managed, your triggers are less likely to cause symptoms.

Also, your asthma symptoms can be caused by more than one asthma trigger at the same time. If this happens, it could cause a stronger reaction - for example, if you have a cold and you also come into contact with a cat. This can be why sometimes triggers do cause symptoms and why sometimes they don’t.

How do you know which asthma triggers affect you?

If you understand which things trigger your asthma you might be able to avoid them. Sometimes it’s obvious what your triggers are. Sometimes it’s not. Asking yourself these two questions can help you work out which triggers affect you:

1. Have I got any obvious triggers?

Often it’s obvious which things trigger your asthma - for example, when your symptoms start after you’ve come into contact with a cat or dog. Or you might find that your asthma symptoms are set off by a food allergy, alcohol, cigarette smoke or smoke from open fires.

2. What are your other triggers?

Sometimes it’s not easy to pinpoint exactly what triggers your asthma. This is because some triggers are invisible (such as grass pollen); you may have more than one trigger; and sometimes you may have a delayed reaction to a trigger. A bit of extra detective work may be needed - try keeping a diary of activities and symptoms to help you spot any patterns.

Can you avoid asthma triggers?

"It’s impossible to avoid all triggers but you can cut your risk of developing asthma symptoms when you’re exposed to them," says Dr Samantha Walker, Asthma UK.

Some asthma triggers are easily avoidable, such as cigarette smoke, pets and alcohol. But it’s impossible to avoid many common asthma triggers – things like pollen, pollution, colds, dust mites and cold weather.

How can you deal with asthma triggers?

There are proven steps you can take to cut your risk of asthma triggers causing asthma symptoms or an asthma attack:

1. Take your preventer medicine every day

The best way to help your body cope well with any asthma triggers is to take your preventer inhaler every day as prescribed. Your preventer medicine is specially designed to work away in the background to help reduce sensitivity and irritation in your airways. Taking it every day means there’s less chance of a reaction if you come into contact with any triggers - so you’re more likely to able to go to work, have fun with your family and enjoy socialising with friends.

2. Use a written asthma action plan

There’s space on your written asthma action plan to note down your triggers to help you spot when your asthma needs extra help. Using an action plan cuts your risk of ending up in hospital due to your asthma, as it contains all the information you need to look after your asthma well and reduce your likelihood of getting symptoms. If you haven’t got one, download an asthma action plan now and fill it in with your GP or asthma nurse as soon as possible.

3. Go for an asthma review at least once a year

An asthma review gives you and your GP or asthma nurse a chance to make sure your written asthma action plan is up to date. It’s important to check regularly that you’re taking the right medicines in the right way and at the right doses so they’re always giving you the best protection against your triggers as possible.

If you’re taking your medicines as prescribed but still having asthma symptoms, speak to your GP or asthma nurse so you can come up with a plan to improve things. It might be that something as simple as a change of inhaler technique could solve the problem. 

Last updated February 2016

Next review due February 2019