What Exactly is ‘Thunderstorm Asthma?’

It’s no laughing matter in Australia, where a perfect storm of factors combined last week to cause a freak thunderstorm that has left researchers searching for answers.

Eight people were killed in the Melbourne area, and 8,500 people went to emergency departments, including one person who remains in intensive care.

Now questions are being asked about the response to the mass asthma event, a phenomenon health experts around the world have described as unprecedented.

Janet Davies, Ph.D., the head of the Allergy Research group at the Queensland University of Technology in Brisbane, told Healthline the severity of the event was impossible to predict.

“Due to their rarity and the interactions of complex contributing factors we have not had systems to predict or prepare for thunderstorm asthma events,” she said. “Whilst there have been a number of thunderstorm asthma events in Melbourne and elsewhere in the past, this tragic event last week was particularly severe and affected a large number, in fact many more people, than before.”

How storms stir up asthma

The first instance of thunderstorm asthma occurred in Melbourne in 1987.

Other cases have been reported in Australia’s southeast as well as in England and Italy.

Normally, grass pollen is too large to enter the lungs. Instead, it is filtered through the nose, causing symptoms of hay fever for those with an allergy.

During a thunderstorm, however, grass, tree, and weed pollens, as well as mold spores, are lifted into the air. Moisture from storms then causes these pollens to rupture into tiny particles that are then small enough to enter the lungs.

Compounding this, winds during thunderstorms cause these small particles to float around at ground level where they can easily be inhaled.

All this can trigger asthma symptoms, including shortness of breath, wheezing, coughing, and chest tightness.

Davies told Healthline grass pollen is the number one outdoor aeroallergen worldwide. Between 45 percent and 65 percent of people who have allergies have a sensitivity to grass pollen.

In the United States, allergies are the sixth leading cause of chronic illness. The Centers for Disease Control and Prevention (CDC) estimates that 25 million Americans have respiratory allergies.

“Chances are, you know someone with outdoor allergies,” Tonya Winders, chief executive officer and president of the Allergy and Asthma Network, told Healthline.

“In people with asthma and allergies,” she said, “the immune system identifies the allergens as dangerous invaders and produces protective antibodies in an effort to destroy them. Airways become inflamed and swollen, and airflow is restricted.”

What caused such a mass outbreak?

Although thunderstorm asthma has occurred before in Melbourne, researchers are still unable to understand exactly what factors conspired to cause a mass asthma outbreak.

“Thunderstorm asthma epidemics do not happen every time there is storm activity on high grass pollen count days,” Davies told Healthline. “There are a number of complex weather factors — e.g., wind patterns, changes in temperature and humidity — that interact with the load of allergens in the air. Local factors like the type of grass, the timing and intensity of grass pollination, are likely to be important.”

Although there are no recorded cases of thunderstorm asthma in the United States, Winders says they likely have occurred, just not on the same scale as in Melbourne.

A study published in 2008 in the medical journal Thorax showed that in Atlanta between 1993 and 2004, 24,350 emergency department visits due to asthma occurred on days following thunderstorms.

Scientists have warned thunderstorm asthma could become more prevalent due to the impact of climate change.

“Climate scientists say pollen allergy seasons could become longer and thunderstorms more potent with heavier rains and strong winds,” Winders said.

Source:
http://www.healthline.com