A Perfect Storm: Asthma and Weather

Weather can exacerbate asthma, and one specific trigger is thunderstorm activity. Generally speaking, windier days increase pollen counts, and windless, rainy days lower pollen counts. When thunderstorms roll across the horizon, they turn expected pollen situations upside down.

Epidemic Thunderstorm Asthma (ETSA) describes epidemic-level acute bronchospasm events pursuant to thunderstorms. The exact mechanism that leads to widespread asthma exacerbations is not well understood.

It appears that thunderstorms push a high burden of airborne allergens to ground level, and rupture of wet pollen granules by osmotic shock follows. This creates a particle load that people with asthma can't tolerate. Of interest, people with allergic rhinitis are also highly susceptible to ETSA.

ETSA events have been documented worldwide. In 2016, residents of Melbourne, Australia, experienced a series of thunderstorms that caused extensive asthma-like respiratory events. An analysis published in theInternal Medicine Journaldiscusses this event in particular, and raises issues that healthcare providers around the world need to be aware. This analysis is based on an anonymous survey that was distributed widely among staff and volunteers who had delivered care during the thunderstorm.

More than 25% of respondents had experienced a healthcare episode that resembled asthma during the ETSA event. Most of them did not seek help from licensed healthcare providers. Among individuals who reported ETSA-like symptoms, 44% indicated that they had been diagnosed with asthma previously. Almost 3/4 of respondents reported having allergic rhinitis. Individuals with allergic rhinitis or asthma were 2.77 and 1.6 times, respectively, more likely to have experienced ETSA-like symptoms than others. Individuals who reported their ethnicity as Asian were more than 3 times as likely as others to have experienced ETSA -like symptoms.

Of interest, individuals who indicated that they had stayed indoors for the most part had episodes of asthma-like symptoms similar to others. This finding refutes findings from other studies that advise people with asthma to stay inside, and close the windows.

Thunderstorms can be the event that precipitatesa diagnosis of asthmain previously undiagnosed individuals. As various areas of the world experience thunderstorms of unprecedented severity, it's critical for healthcare providers to heighten awareness of respiratory conditions precipitated by severe weather conditions.

Reference

Clayton-Chubb D, Con D, Rangamuwa K, Taylor D, Thien F, Wadhwa V. Thunderstorm Asthma - Revealing a hidden at-risk population. Intern Med J. 2018 Mar 23. doi: 10.1111/imj.13800. [Epub ahead of print]