Mahboobeh Mahdavinia, MD, FAAAAI, PhD

How Climate Change is Making Your Patients' Allergies Worse

As climate change intensifies, it is not just the environment that suffers—seasonal

are getting worse, too. Global warming has led to increased droughts, wildfires, intense storms, heat waves, and rising sea levels, factors that can contribute to allergies and asthma.

According to the American Public Health Association, the 3 main causes of allergy include ambient air pollution, mold, and pollen.

 The organization also reported that 30% of adults and 40% of children experience nasal allergies.

Featuring Scott Commins, MD, PhD (top left), Sharmilee Nyenhuis, MD (bottom left), Mahboobeh Mahdavinia, MD, PhD (top right), and Kent Lam, MD (bottom right)

Credit: UNC School of Medicine, UChicago Medicine, McGovern Medical School, Macon & Joan Brock Virginia

2025 American Academy of Allergy, Asthma, & Immunology (AAAAI) 

spoke with several experts on climate change’s impact on allergies, exploring strategies clinicians can adopt to mitigate worsening allergic conditions.

, from the University of Texas Health Houston

 from Eastern Virginia Medical School at Old Dominion University

Extended Pollen Seasons and Increased Allergen Potency

Nyenhuis emphasized that pollen seasons are lengthening, especially in the western and southwestern United States, where freeze days have increased by nearly 20.

 This prolonged exposure intensifies symptoms and raises the risk of new allergies. She also noted that air pollution, particularly diesel particles, can amplify pollen’s allergenicity, worsening allergic reactions.

To help patients, Nyenhuis recommended indoor air filtration, wearing masks outdoors, and using hyper-local pollen data instead of historical weather app forecasts, which are becoming less reliable due to climate change.

Air Pollution’s Role in Allergy Development

Mahdavinia explained that air pollutants disrupt the respiratory tract’s epithelial barriers, leading to inflammation and microbiome imbalances in the nose and lungs.

 This can eliminate beneficial bacteria, allowing harmful microbes to thrive and increasing allergy risks. Mahdavinia called for expanded pollen monitoring and broader allergen testing as plant distributions shift.

Climate Change and Emerging Food Allergies

Commins discussed pollen food syndrome, in which pollen absorbed through the skin triggers food allergies.

 He also warned about the rising prevalence of alpha-gal syndrome, a meat allergy caused by tick bites. Warmer winters have expanded tick populations, increasing cases in the US, Europe, Australia, and Asia.

As climate change drives new allergy risks, clinicians must stay alert for evolving conditions such as pollen food syndrome and alpha-gal syndrome. Experts stress the importance of refining allergy diagnostics, improving access to immunotherapy, and implementing preventive strategies to protect patients in an increasingly allergenic environment.

Relevant disclosures include GlaxoSmithKline for Nyenhuis, GENZYME CORPORATION, Optinose US, Inc, and Blueprint Medicines Corporation for Mahdavinia, Regeneron Healthcare Solutions, Genetech USA, and AstraZeneca Pharmaceuticals for Commins, and Optinose US, AERIN MEDICAL, GENZYME CORPORATION, Medtronic, GlaxoSmithKline, Regeneron Pharmaceuticals, and AstraZeneca Pharmaceuticals for Lam.

. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.apha.org/-/media/files/pdf/topics/climate/asthma_allergies.pdf. Accessed March 20, 2025.

Derman, C. Adapting Allergy Care Due to Increased Pollen Seasons, with Sharmilee Nyenhuis, MD. HCPLive. March 1, 2025. 

https://www.hcplive.com/view/adapting-allergy-care-due-increased-pollen-seasons-sharmilee-nyenhuis-md

Derman, C. How Air Pollutants Contribute to Allergies, with Mahboobeh Mahdavinia, MD, PhD. HCPLive. March 1, 2025. 

https://www.hcplive.com/view/how-air-pollutants-contribute-to-allergies-with-mahboobeh-mahdavinia-md-phd

Derman, C. Climate Change’s Impact on Allergies, with Scott Commins, MD, PhD. HCPLive. March 2, 2025. 

https://www.hcplive.com/view/climate-change-s-impact-on-allergies-scott-commins-md-phd

Articles

Climate change worsens allergies by lengthening pollen seasons, increasing air pollution, and driving new food allergies. Experts offer strategies for clinicians.

How Climate Change is Making Allergies Worse—And What Clinicians Can Do

How Air Pollutants Contributes to Allergies, with Mahboobeh Mahdavinia, MD, PhD

 sat down with Mahboobeh Mahdavinia, MD, PhD, from the department of medicine and pediatrics at the University of Texas Health Houston, to discuss her team’s presentation, “How to Adapt the Practice of 

“The main change that we're concerned about is the pollen count,” Mahdavinia said.

This echoes the statement from Sharmilee Nyenhuis, MD, a professor at the University of Chicago, who spoke at the meeting about the 

 and the importance of collecting hyper-local pollen data instead of relying on historical data from weather app pollen forecasts.

 She said that the west coast and the southwest had nearly 20-day increases in freeze days which lengthens the pollen.

Mahdavinia is most concerned about the pollen count because not only are allergic patients exposed to allergens longer, but a higher pollen count increases the likelihood of becoming allergic.

She said air pollutants contribute to allergies by disrupting the epithelium barrier by causing irritation and inflammation. Pollutants can also impact microbes in the nose and lungs and may kill some good bacteria, leaving room for pathogens.

In response to climate change, investigators have expanded measuring pollen in different regions and pollen in specific plants that did not use to be in that area.

“That would be one area that's needed now—to look more broadly for different pollens and potentially test for larger panels,” Mahdavinia said.

Mahdavinia emphasized the importance of individualized allergen immunotherapy. A barrier to allergen immunotherapy is that the allergen imitator is not paid well by insurance—or at all. This makes it hard for disadvantaged patients to receive immunotherapy.

“Changes in the insurance policies could be very helpful if they universally cover hydrogen immunotherapy that would be beneficial to many patients that now cannot get [it],” Mahdavinia said.

Relevant disclosures for Mahdavinia include GENZYME CORPORATION, Optinose US, Inc, and Blueprint Medicines Corporation.

Mahdavinia, M. How to Adapt the Practice of Allergy and Immunology to Climate Change. Session presented at AAAAI 2025 in San Diego on March 1.

Climate change is significantly impacting allergy and immunology practices, primarily due to increased pollen counts and extended pollen seasons. This results in prolonged allergen exposure and a higher likelihood of developing allergies. Air pollutants exacerbate allergies by disrupting the epithelial barrier and affecting nasal and lung microbes. To address these challenges, there is a need for expanded pollen measurement and individualized allergen immunotherapy. However, insurance coverage for allergen immunotherapy remains inadequate, posing a barrier for disadvantaged patients. Policy changes could improve access to necessary treatments for these patients.

At AAAAI 2025, HCPLive spoke with Mahdavinia about how climate change impacts allergies.