Thunderstorm-Triggered Asthma Could Provide Opportunities for Intervention, Researchers Say

Researchers in Australia—where thunderstorm-triggered asthma killed 10 people and sent 3400 people to emergency departments in 2016—recently reviewed what is known and unknown about this phenomenon and suggested that ways to better stratify at-risk individuals are needed.

So-called thunderstorm asthma (TA) typically happens during thunderstorms in pollen season across the world. When TA struck Melbourne, Australia, in November 2016, emergency services were overwhelmed, the researchers noted. Although uncommon, TA events are predicted to increase in frequency. Research has indicated there will be an increase in extremes of weather and intensity of heavy rainfall episodes, including thunderstorms. Given the impact of climate change, changing agricultural practices, and the role of air pollution, additional research on how to predict these events is key, researchers said.

TA is believed to occur when specific meteorological and aerobiological conditions combine to affect predisposed patients, including those with asthma, those without asthma, those with pollen allergies, and those with rhinitis. Symptoms such as breathlessness, cough, or wheeze occur suddenly in such patients due to bronchospasm and often require emergency medical treatment and/or hospitalization.

Ideally, the researchers wrote, an early warning system based on environmental factors to alert emergency services and allow communication to at-risk individuals is necessary, but such a system is currently difficult to implement given a high false alarm rate.

Additionally, those with known asthma should have their treatment optimized and be educated on adherence. Seasonal rhinitis patients should be evaluated for asthma symptoms and have their rhinitis treatment optimized via nasal corticosteroids. Grass pollen immunotherapy may offer opportunities to treat both allergic rhinitis and asthma in these circumstances.

Lastly, development of potential biomarkers could lead to interventions for at-risk patients.

During TA, thunderstorm outflows can concentrate aeroallergens, most commonly grass pollen, down to the ground. Normally, these pollens are too big to get into the lungs. But during TA, they rupture due to osmotic shock from the humidity and rain, and become aerosolised, capable of penetrating lower airways in sensitized individuals.

Studies on the individuals affected in 2016 found TA to be associated with allergic rhinitis, ryegrass pollen sensitization, pre-existing asthma, poor adherence to inhaled corticosteroid preventer therapy, hospital admission for asthma in the previous year, and outdoor location at the time of the storm. Patients without a prior history of asthma were also affected.

Reference

Harun NS, Lachapelle P, Douglass J. Thunderstorm-triggered asthma: what we know so far [published online May 6, 2019]. J Asthma Allergy. doi: 10.2147/JAA.S175155.