Factsheet

Thunderstorm asthma

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By football grand final weekend, you should be taking your hay fever nasal spray, asthma preventer, or both – and don’t stop until New Year’s Day (most adults with asthma need to take a preventer all year, not just in springtime).

What is thunderstorm asthma?

Thunderstorm asthma is a potent mix of pollen and weather conditions that can trigger severe asthma symptoms in a large number of people over a short period of time. 

Thunderstorm asthma may occur when a storm strikes on a hot and windy day during pollen season (early October - late December), when there are high levels of pollen in the air combined with a certain type of weather event.

When a storm front hits, the pollen grains absorb the moisture and burst into tiny particles. The thunderstorm winds blow the particles down to ground level, where they can be inhaled deep inside the lungs and trigger a serious asthma flare up. 

Weather conditions like these can also lead to breathing problems being experienced not only by people with asthma but those who have seasonal hay fever. People who wheeze and sneeze with hay fever from pollens during spring are most likely to be affected, even if they have not been diagnosed with asthma before.

November 2016: Victorian Thunderstorm Asthma Event

On the evening of Monday 21 November 2016, Victoria experienced severe thunderstorm activity. The thunderstorm was followed by a thunderstorm asthma event, the likes of which in terms of size and severity was unprecedented. It resulted in thousands of people developing breathing difficulties in a very short period of time and placing increased pressure the ambulance service and hospital emergency rooms. 

Who is most at risk of thunderstorm asthma?

Those at increased risk of thunderstorm asthma include people with both asthma and seasonal hay fever, as well as those with past or undiagnosed asthma. People with seasonal spring hay fever who have never had asthma are also at risk.

Thunderstorm asthma can affect people living in metropolitan, regional or rural areas, even if they don't have a history of asthma.

What are the symptoms of asthma and hay fever?

People with asthma may experience one or more of the following common symptoms:

  • Wheezing - a high-pitched sound coming from the chest while you are breathing
  • Breathlessness
  • A feeling of tightness in the chest
  • A persistent cough

A person’s asthma symptoms can vary over time – sometimes they will have no symptoms, especially when asthma is well-controlled – and symptoms often vary from person to person.

People with seasonal hay fever may experience one or more of the following common symptoms:

  • Runny nose
  • Itchy nose
  • Sneezing
  • Itchy, watery eyes

People with springtime hay fever (allergic rhinitis)

If you have seasonal allergic rhinitis (springtime hay fever), there is a chance you could have an asthma attack if you are outside in gusty wind during a thunderstorm in a place where there is ryegrass pollen in the air (most of south-eastern Australia). This can happen even if you don’t have asthma. The risk is highest between October and the end of December.

What you can do to keep safe

  • During spring and early summer, use a corticosteroid nasal spray (e.g.Avamys, Azonaire, Beconase, Budamax, Budesonide, Flixonase, Nasonex,Omnaris, Rhinocort, Sensease, Telnase). Start at the beginning of September and continue to the end of December.
  • Follow the pollen counts and weather forecasts during spring and early summer so you know if a storm is coming.
  • Just before and during storms with wind gusts, get inside a building or car with the windows shut and the air conditioner switched to recirculate/recycled.

People with asthma

If you have asthma and pollen allergy, you could have a severe asthma attack if you are outside in gusty wind during a springtime thunderstorm in a place where there is ryegrass pollen in the air (most of south-eastern Australia).

How do I know if I’m allergic to ryegrass pollen without having allergy tests?

Signs can include having asthma symptoms that tend to flare up in spring, and having allergic rhinitis (hay fever). If you’re not sure, follow the safety steps anyway.

What you can do to keep safe

  • Keep taking your preventer medication as prescribed. If you do not normally use a preventer all year, you should use it during September–December if you are going to be in an area where there is ryegrass pollen.
  • Follow the pollen counts and weather forecasts during spring and early summer so you know if a storm is coming.
  • Make sure your written asthma action plan is up to date and includes thunderstorm advice – talk to your GP.
  • Avoid being outdoors just before and during thunderstorms, especially in cold wind gusts that come before the rain. Get inside a building or car with the windows shut and the air conditioner switched to recirculate/recycled.

For more information

First Aid for Asthma Chart - step by step instructions on what to do in an emergency. 

Written asthma action plans 

How-to video library – how to use your inhaler 

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