A rumbled sky, some lightning and suddenly a violent respiratory crisis: it is the scenario feared by people with asthma or seasonal allergies. This phenomenon, called asthma of thunderstorms, intrigues researchers for several decades and raises a simple but scary question: why can a thunderstorm be enough to trigger a serious crisis?
Asthma of thunderstorms, an unknown but real phenomenon
In November 2021, The Journal of Allergy and Clinical Immunology published a study confirming that thunderstorms could cause or worsen asthma attacks. Asthma of thunderstorms mainly affects people with seasonal allergic rhinitis, but does not spare other asthmatics. Contrary to the widespread idea that rain cleanses the air of pollens, stormy conditions actually create an unusual concentration of breathable particles. Wind gusts and descending currents cause pollen and mold to the ground, while electrical activity fragments pollen grains into even thinner particles. Result: they easily penetrate in the nose, sinuses and lungs. Spotted for the first time in the 1980s in Australia and the United Kingdom, this phenomenon has known since a regular increase in the cases identified.
Factors that increase the risk of storms asthma
The study reveals that 65 % of people allergic to pollens say they have already suffered from stormy asthma. Almost half of these patients had to be hospitalized in an emergency. According to Harvard University, several indicators increase the probability of developing a crisis during a thunderstorm:
- Poorly controlled asthma symptoms;
- A low score for the rapid expiration test;
- High levels of IgE antibodies specific to Ray-Grass pollen;
- A larger number of eosinophiles in the blood;
- A high level of exhaled nitric oxide, marker of pulmonary inflammation.
These factors do not guarantee that a crisis is triggered at each storm, but make it possible to better identify risk profiles, especially in regions frequently exposed to bad weather.
Prevention and tracks to limit crises
Researchers insist on the need to better anticipate this type of climate event. “”When asthma of thunderstorms affects a large part of the population, emergency rooms can be overwhelmed, as in 2016 in Melbourne (Australia). A better understanding of the moment when these events are expected could lead to advanced alert systems, better preparation of emergency rooms, or even preventive treatment“, they explain. The weather forecasts associated with pollen data could thus make it possible to set up targeted health alerts and strengthen prevention with the most vulnerable patients.