There are few things as ominous as thunder. It says there's a storm coming, or somewhere lightning has struck. But can a thunderstorm actually make you sick? The answer is yes! A recent study looked at the rare phenomenon called "thunderstorm asthma," and under the right conditions, a thunderstorm can actually trigger an asthma attack.
The first recognized occurrences of "thunderstorm asthma" were in 1983 in Birmingham, England, and in 1987 in Melbourne, Australia, when violent thunderstorms and associated high pollen counts seemed to have been connected to a widespread wave of asthma attacks. Since that time, a number of other cases have been reported in England and Italy. In the fall of 2016, a similar band of strong thunderstorms moved across southeastern Australia and apparently triggered another rash of asthma attacks. In Melbourne, eight people died and more than 8,000 went to the emergency room. Clearly, this was no fluke—and it was serious.
But the phenomenon wasn't understood until recently. One puzzling thing about thunderstorm asthma is that rain normally helps people with allergic asthma by washing pollen out of the air. So why do certain severe storms have the opposite effect? Another perplexing detail was that the areas with the asthma outbreaks were dominated by rye grass pollens, which are normally too large to cause asthma symptoms because they are usually trapped in the nose and sinuses before they reach the lungs.
This spring, researchers at the University of Georgia studied the 2016 event in Australia and solved the mystery. Their study, which was published in the Journal of Applied Meteorology and Climatology, found that the primary culprit was a specific airflow pattern, aided by humidity and electricity. Downdrafts of cold air within the thunderstorm concentrate particles of pollens and mold spores and then sweep them into the high humidity of the clouds. There, the wind, humidity and—to a lesser extent lightning—combine to rupture the pollen and spores and break them down into much smaller fragments that can pass through the nose and sinuses into the lungs.
Finally, gusty winds can redistribute these highly concentrated, irritating particles in the area around the storm. If this happens near a large population center, like Melbourne, Australia, you have all the ingredients for a "perfect storm," capable of causing severe asthma attacks in people who are sensitive to these allergens.
Does this mean that people living with asthma should hold their breath every time they hear thunder rumble? Not necessarily. First, these specific meteorological events are very rare and depend on the right combination of weather, allergens and a sensitive population. The study authors say that their models of these elements could someday lead to a way to predict when thunderstorm asthma might occur and allow health officials to issue warnings. Until then, if you have asthma and are sensitive to allergens like pollen, restricting outdoor activities after a particularly severe thunderstorm might be wise.
Thunderstorm asthma may be a rarity, but living with asthma, avoiding triggers and controlling symptoms can be an everyday challenge. The American Lung Association has information and tools to help you learn about and control asthma symptoms.