Thunderstorms linked to surge in asthma ER visits, new study shows

ORLANDO (Nov. 6, 2025) – A new study finds that thunderstorms can trigger sharp increases in asthma-related emergency department (ED) visits, underscoring the importance of storm preparedness for people with asthma. The research is being presented at the 2025 Annual Scientific Meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in Orlando.

“Thunderstorm asthma” is a well-documented environmental phenomenon internationally, but studies in United States in areas with heavy pollen have been limited. According to the World Allergy Organization, thunderstorms are considered a risk factor for asthma attacks in patients suffering from pollen allergy.

Researchers analyzed 4,439 asthma-related ER visits across three Wichita, KS hospitals from January 2020 to December 2024. Using meteorologic records, they identified 38 thunderstorm days during this period.

Key findings included:

• 14% of all asthma-related ER visits (627 cases) occurred on just 38 storm days, which represented only 2% of the calendar days in the study period.
• The average number of asthma visits was nearly 18 per day during thunderstorms, compared to just 3 on non-storm days.
• Older age was the only demographic factor linked to increased risk of storm-related asthma ER visits. Gender, location, and whether patients were admitted or discharged did not significantly affect the likelihood of visiting during a storm.

“These results confirm that thunderstorms can pose a serious health risk for people with asthma, even in the United States,” said Diala Merheb, MD, lead author of the study. “Because storms are unpredictable, patients and healthcare providers should include storm-specific precautions in asthma action plans.”

The researchers note that storm-related surges in asthma cases place a significant burden on emergency departments. By recognizing the connection between thunderstorms and asthma exacerbations, communities and healthcare systems can develop preparedness strategies to protect vulnerable populations and reduce strain on hospitals.

Says allergist Selina Gierer, DO, ACAAI member and one of the study authors, “If you or your child has asthma, it’s smart to think about thunderstorms the same way you prepare for high-pollen days or cold weather. “Understanding triggers and having a clear plan can help avoid emergency room visits.”

Abstract Title: Thunderstorm-Associated Increases in Asthma ED Visits in a Midwestern US City: A Five-Year Review (Full abstract below)

Presenter: Diala Merheb, MD

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THUNDERSTORM-ASSOCIATED INCREASES IN ASTHMA ED VISITS IN A MIDWESTERN US CITY: A FIVE-YEAR REVIEW

D. Merheb^*1, T. Nguyen², S. Gierer², H. Chang¹, 1. Wichita, KS; 2. Kansas City, KS.

Introduction: Thunderstorm asthma is an environmental phenomenon marked by surges in asthma exacerbations during or shortly after storms. While documented internationally, few studies have evaluated this effect in U.S. regions with high allergen burdens. This study assesses whether thunderstorms are associated with increased asthma-related emergency department (ED) visits in Wichita, Kansas, and explores demographics.

Methods: This study was approved by the Ascension Health Institutional Review Board. We conducted a retrospective analysis of 4,439 asthma-related ED visits from January 1, 2020, to December 31, 2024, across three hospitals in Wichita. Thunderstorm days (n = 38) were identified using meteorologic records from the National Centers for Environmental Information. Each ED visit was classified as occurring on a storm or non-storm day. Daily asthma admissions were compared using a Mann-Whitney U test. Multivariable logistic regression assessed the relationship between storm-day admissions and age, gender, zip code, and ED disposition.

Results: Of 4,439 asthma-related ED visits, 627 (14.1%) occurred on 38 thunderstorm days. The mean number of admissions on storm days (17.91) was significantly higher than on non-storm days (3.09) (Mann-Whitney U = 41,787.5; p < 5.55 × 10?²²). Storm days accounted for only 2% of calendar days but over 14% of asthma visits. Regression identified older age as a significant predictor of storm-day presentation (β = 0.0071, p = 0.002). Gender, zip code, and disposition were not significant.

Conclusion: Asthma-related ED visits rose significantly on thunderstorm days in Wichita. Findings support storm-specific public health preparedness, including education and modifications to asthma action plans to ease healthcare burden.