Asthma-related emergency department (ED) visits jumped significantly on days when thunderstorms occurred, based on data from more than 4000 visits. The findings were presented at the American College of Allergy, Asthma, and Immunology (ACAAI) 2025 Annual Meeting.

“Thunderstorm asthma is an environmental phenomenon marked by surges in asthma exacerbations during or shortly after storms,” Diala Merheb, MD, internal medicine resident at the University of Kansas Medical Center, Kansas City, Kansas, and colleagues, said in their abstract. However, documentation of this effect in areas of the US with high allergy burdens are limited, they noted. 

The researchers reviewed data from 4439 asthma-related ED visits between January 1, 2020, and December 31, 2024, from three hospitals in Wichita, Kansas. Each visit was classified as occurring on a storm day or nonstorm day. A total of 38 thunderstorm days were identified using meteorologic records from the National Centers for Environmental Information. 

Overall, 14% of the asthma-related ED visits occurred on one of the 38 storm days, with a mean of 17.91 asthma-related ED admissions on storm days compared to a mean of 3.09 on nonstorm days.

“Storm days accounted for only 2% of calendar days but over 14% of asthma visits,” the researchers wrote. In a regression analysis, older age was a significant predictor of storm day ED asthma visits, but sex, zip code, and disposition were not significant predictors, they noted.

The findings were limited by several factors, including the focus on a single region. However, the results support storm-specific preparedness that includes education and modification of asthma action plans to support patients and ease healthcare burdens, the researchers concluded. 

Findings Can Inform Clinical Care

“Understanding the relationships between environmental factors, such as thunderstorms and wildfires, is crucial for public health preparedness and clinician and patient awareness,” said Sucharita Kher, MD, a pulmonologist and vice chair of clinical operations and quality for the Department of Medicine at Tufts Medical Center, in an interview.

Although the relationship between thunderstorms and asthma visits has been noted, the magnitude of the effect in the current study was striking, said Kher, who was not involved in the study. The findings highlights how environmental triggers can potentially overwhelm healthcare systems, she told Medscape Medical News. The impact of older age as a predictor of storm-day asthma exacerbations was intriguing as well, she added.

“Advise patients to review and follow their asthma action plans, especially during thunderstorm season,” Kher told Medscape Medical News. “Patients, particularly older patients should keep their rescue inhaler accessible at all times, monitor symptoms closely, and, if available, use a peak flow meter to assess asthma control,” she said.

The takeaway for healthcare institutions is to prepare for potential surges in ED visits and inpatient admissions during and immediately after thunderstorms, she said.

The retrospective design of the study limits causal inference, said Kher. “Prospective studies to evaluate proactive and preventive interventions, such as early warnings and medication adjustments before storms, will be valuable in the future,” she said.

The study received no outside funding. The researchers disclosed having no financial conflicts of interest. Kher disclosed serving as a local leadership board member for the American Lung Association of Massachusetts.