What is thunderstorm asthma?
Thunderstorm asthma is triggered by a combination of grass pollen in the air and certain thunderstorm conditions.
It can occur when pollen grains are drawn up into the clouds as a thunderstorm forms. The pollen grains absorb water, swell and burst open. Particles containing pollen allergens are released and are so small that they can be breathed into the lungs. The weather conditions can push these tiny particles down to ground level then along the ground in the winds that come ahead of the rain.
Thunderstorm asthma usually affects people in the windy period before the rain starts. It usually occurs in spring and early summer.
Even people who have never had asthma before can be affected. If symptoms become severe or life-threatening, call triple zero (000) and ask for an ambulance — say it is an asthma emergency.
Watch this video from Better Health Channel about thunderstorm asthma. It's also available with subtitles in languages other than English on the Health Translations website.
Who is at risk of thunderstorm asthma?
Thunderstorm asthma can affect people of any age. You are more likely to be affected if you:
- have asthma or have had asthma in the past
- get seasonal hay fever that is triggered by pollens (this is also known as allergic rhinitis)
- are allergic to ryegrass pollen
- have undiagnosed asthma or are affected by pollen without being aware of it
If none of these apply to you, your risk is low.
The risk of thunderstorm asthma is highest in adults who are sensitive to grass pollen and have seasonal hay fever (with or without known asthma).
What are the symptoms of thunderstorm asthma?
If you have thunderstorm asthma, a thunderstorm might trigger one or more of these symptoms:
- shortness of breath
- tightness in your chest
- wheezing when you breathe
- persistent coughing
The symptoms of thunderstorm asthma can get worse very quickly. If breathing becomes difficult, seek treatment immediately.
How is thunderstorm asthma treated?
If you are experiencing thunderstorm asthma, follow these instructions.
If the symptoms are moderate or mild, begin asthma first aid using your asthma reliever inhaler. Also, if you have hay fever preventer medication, such as intranasal corticosteroid sprays or combined intranasal/antihistamine sprays, take as directed.
If the breathing problems are severe, call triple zero (000) and ask for an ambulance — say it is an asthma emergency — and begin asthma first aid using your asthma reliever inhaler.
You should also call triple zero if you’re experiencing thunderstorm asthma and you don’t have an inhaler.
If you are with someone who is experiencing asthma symptoms, sit the person upright, stay with them and be calm and reassuring. Follow the instructions above.
Can thunderstorm asthma be prevented?
If you have or have had asthma or hay fever, you can help protect yourself from thunderstorm asthma by managing those conditions well and planning for emergency situations.
See your doctor for a diagnosis and to develop a personalised asthma action plan or hay fever treatment plan.
Your plan should include what preventive medications you can take to manage your condition and what you should do in an asthma emergency. You should review your plan regularly with your doctor.
How can I avoid thunderstorm asthma triggers?
It’s a good idea to check pollen counts and weather forecasts with these sources:
- the Bureau of Meteorology (BOM) site or the BOM Weather app
- the Australian Pollen Allergen Partnership, which shares pollen count in some cities both online and via an app
- the AirRater app, which links your symptoms to environmental conditions, including pollen counts, and can notify you of triggers
If a thunderstorm is approaching on a high pollen count day, it is a good idea to:
- make sure you have your reliever medication with you
- stay inside a building or a car, especially during the wind gusts before the rain
- close your doors and windows
- if an air conditioner is on, set it to recirculate air
Face masks don’t protect against the tiny particles that cause thunderstorm asthma.
When to seek help
If breathing problems are severe, call triple zero (000) and ask for an ambulance — say it is an asthma emergency.
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Last reviewed: December 2019