A fifth death has been attributed to Melbourne’s “thunderstorm asthma” emergency on Monday night and it was lucky there were not more, according to the state’s health minister.
More than 8000 people suffered breathing problems when a severe storm combined with an extreme pollen count to cause what is being described as thunderstorm asthma. Six people remain in intensive care.
The recent severe thunderstorm in Melbourne caused hospitals across the city to be put on emergency alert as thousands of people called ambulance services, reporting severe breathing difficulties.
Emergency departments were overwhelmed, with the patient overflow having to be directed to day units.
So what do we know about thunderstorm asthma?
Asthma epidemics associated with sudden changes in weather are well documented globally, especially in Europe, Australia and North America.
Interestingly, different causes have been ascribed to the sudden outbreak of severe asthma. Considerable research effort was put into investigating the cause of these outbreaks in the 1970s and ’80s.
Melbourne in particular has had several well-documented thunderstorm-related asthma epidemics.
Research effort around the world was initially focused on whether there was a single dominant cause of asthma epidemics during a severe thunderstorm. It is now very clear, however, that the causes are location-specific.
Thus, the cause of an asthma epidemic during a thunderstorm in Melbourne may not be the same as the cause of an asthma epidemic during a thunderstorm in Birmingham, United Kingdom.
Having said that, high winds and rain in the context of high levels of air allergens cause asthma epidemics. But the specific allergen responsible may be different.
Could we have seen this coming?
There are many common threads in all reports of thunderstorm-related asthma — a high concentration of potentially allergenic material such as that in late spring in Melbourne (pollen grains or fungi), a thunderstorm that sweeps up the allergens, which burst when wet and release very small particles (such as starch granules or fungal spores).
The high level of these small particles that can travel deep into our lungs induces severe asthma attacks in sensitive individuals.
Keeping an eye on pollen counts and any forecasts of turbulent weather will prepare you for possible asthma attacks.
What can we do to avoid them?
There are many actions we can take to minimise the risk of weather-related asthma attacks.
The main idea is to keep out of the way of allergens. So, stay indoors during rain and wind periods, especially the first 30-60 minutes when the allergens are most prevalent.
Taking your asthma medication (as prescribed by your GP) during a thunderstorm even if you are not feeling unwell may prevent or reduce the severity of the asthma attack.
Hayfever treatments such as antihistamine tablets and steroid nasal sprays may provide some relief. These are most useful if taken before an expected thunderstorm.
However, as thunderstorm asthma is due to allergens reaching the lower parts of the lung and nasal sprays target the nose, you may still get an asthma attack.
As the small allergen particles generated in thunderstorms are very easily and quickly able to penetrate deep into the lungs, these asthma attacks can progress very quickly. Call 000 if you feel the beginnings of an attack.
If you have trouble breathing during a spring storm, even if you do not have asthma, call 000 for help.
Many of those reporting to the emergency department in Melbourne did not have any pre-existing asthma.
This suggests if you have a predisposition towards allergy, the allergens generated by a storm have a high probability of causing a respiratory event.
This doesn’t mean hayfever sufferers should be using long-term asthma medications such as daily preventative puffer medications.
One can get an asthma attack during a severe thunderstorm even without any previous indications of asthma, and as this is probably a rare occurrence it is not necessary to take daily medication.
Keep updated on local pollen counts and weather forecasts, especially in spring; keep your asthma medication up to date; enjoy the spectacle of the thunderstorm from inside your house; and call 000 if your asthma worsens or you feel any breathing difficulty.
Reena Ghildyal is an Associate Professor in Biomedical Sciences at the University of Canberra.