Allergy sufferers often wish for rain, hoping it will wash away all the pollens and molds that stuff up their noses. While rain can indeed provide relief, a violent thunderstorm may have just the opposite effect: An unlucky few may experience a little-known threat called thunderstorm-related asthma.
Not fully understood by scientists, thunderstorm asthma can cause labored breathing for those with asthma and with allergies – including some who have never had breathing difficulties before.
“The phenomenon exists ... it’s not entirely predictable,” said Elizabeth Matsui, an associate professor of pediatrics, epidemiology and environmental health sciences at the Johns Hopkins Children’s Center in Baltimore, Md. Not every thunderstorm increases emergency room visits or cases of asthma, Matsui said. It’s rare, she said, and most who may be vulnerable will not experience it.
Experts are not certain about the exact mechanics of thunderstorm asthma. They hypothesize that heavy thunderstorm winds create updrafts that lift pollen and mold particles from the ground. Beating rain saturates and bursts the particles into tiny pieces.
A downdraft then spreads those small particles into the environment and the air we breathe. Some think that the electrical charge of the storm may make these tiny particles more likely to stick in the lungs when inhaled.
“There’s a lot of small respirable particles floating around that folks can inhale (and that) contain those allergens that cause them to react,” said Susan Kosisky, chief microbiologist with the U.S. Army Centralized Allergen Extract Lab in Silver Spring, Md.
Some of the main allergen culprits behind thunderstorm asthma are thought to be grains of pollen, especially grasses and weeds, and mold spores, particularly Alternaria and Cladosporium, according to Kosisky. Such molds are also associated with asthma in medical studies.
Thunderstorms’ ability to set off asthma attacks has been shown by increased emergency room visits and ambulance calls around the world, according to an overview published in 2012 in the British journal QJM. The authors noted that thunderstorm asthma is an uncommon event: Their review of medical research found only 35 publications. The phenomenon has been followed particularly in Australia, the United Kingdom and Italy.
Experts think some of the upsurge in ER visits related to thunderstorm asthma can be traced to the fact that people with mild asthma or hay fever may not carry rescue inhalers and are therefore unprepared for the impact of the storm.
Turbyville first got interested in the phenomenon when he was chief of allergy, immunology and immunizations at the Fort Knox Army installation. He recalled an instance when several of his patients had more severe reactions than normal to their allergy shots on a day of huge thunderstorms.
Turbyville knew that the risk factors for such reactions are similar to those for asthma, and he wondered whether there was a connection between reactions to allergy shots and thunderstorms. Now he’s working on a study on that possible link.