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Allergy Season is Getting Worse: What to Expect and How to Prepare

Venom Immunotherapy
Seasonal allergies affect millions of people worldwide, and due to a variety of factors, allergy season is becoming more severe and prolonged. Seasonal allergies have begun to extend past the spring into summer, fall, and even early winter in certain areas due to climate change. The main drivers behind this increase are longer growing seasons for plants and agriculture, along with higher levels of carbon dioxide (CO2) that then enhance plant growth and pollen production.1 As the planet continues to transform due to climate change brought on by industry, the expectation is that respiratory health will be negatively impacted while exacerbating conditions such as allergies and asthma.2

The rise in the severity of allergy seasons is linked to a complex system of factors that are based in environmental changes, mostly through human interference. According to D’Amato, Gennaro, et al., increased concentrations of greenhouse gases have warmed the planet substantially since the industrial revolution, causing prolonged heat waves, changes in temperature, increased air pollution, and increased amounts of natural disasters, all of which impact the respiratory health of people. For those who suffer from allergies and asthma, these changes are especially difficult to live with, and it’s crucial to understand the implications of these changes on allergy sufferers and what proactive measures can be taken to help mitigate complications.

Understanding Allergy Seasons

Woman suffering from allergies inside of an office.

Overview of Common Allergens

Allergens are substances that cause an allergic reaction, whether it be localized or systematic, and can be found throughout people’s daily environment. Some of the most common allergens include8: 


  • Pollen 
  • Dust mites 
  • Pets and/or farm animals 
  • Stinging insect venom 
  • Foods 
  • Medication 
  • Contact allergens, such as metals or fragrance 
  • Mold 

Factors Contributing to the Worsening of Allergy Seasons

The increasing severity of allergy seasons, specifically those of pollen allergens, can be attributed to several key factors2: 

  • Climate change 
  • Air pollution 
  • Globalization and migration 

The Effects of Climate Change & Air Pollution

There is a large body of evidence that demonstrates that the temperature of the Earth is rising substantially, which is confirmed through higher ocean temperatures, rising sea levels, glacier melt, and the shrinking of sea ice in the North and South Poles, along with less snow cover in the Northern Hemisphere during winter months.2 

Climate change has a direct impact on allergies and asthma sufferers as these temperature changes affect the length of both growth and pollen seasons for plants and influences mold production. There is also a solid link between climate change, industrialization, and air pollution, which has shown an increase in pollution-related episodes of rhinitis and asthma.2 

According to Williams, Riis, climate change alters pollen patterns within the United States because it lengthens the amount of time during what’s called the “frost-free” season, which is when plants can produce blossoms and sprouts without the risk of frost damage. Since the beginning of the 20th century, the frost-free season has increased by more than two weeks on average and has increased by an average of at least 11 days in the nine distinct climate regions of the U.S. Therefore, pollen production has both increased and pollen season is extended, resulting in more people with pollen allergies having more and longer allergic symptoms. 

Image of fields and polluting agents that effect allergies and asthma.

What to Expect Going Forward

Longer Duration of Allergy Seasons

As mentioned above, the duration of allergy seasons has increased since the start of the industrial revolution. In a 2015 study published by PubMed, the pollen season started on average three days earlier between 2001 and 2010 in the U.S. compared to the 1990’s. The amount of airborne pollen also increased by approximately 40% during this time.5 

Higher Pollen Counts & Increased Allergen Levels

As climate change leads to longer and more intense pollen seasons, trees are releasing more pollen earlier and for a longer amount of time. The allergenicity of this tree pollen also appears to be stronger compared to past pollen seasons, resulting in more symptoms for allergy sufferers.6 This increase in the allergenic response then results in more people going to the doctor or emergency room, putting a higher burden on healthcare systems as people experience reactions and more susceptibility for other infections as their immune system is overloaded.

Worst Cities for Allergies

According to the Asthma and Allergy Foundation of America, there are certain cities in the U.S. that are particularly challenging for allergy sufferers due to high pollen levels, widespread allergen exposure, and limited access to allergy specialists. The top 20 cities of 2024 include: 


  1. Wichita, Kansas 
  2. Virginia Beach, VA 
  3. Greenville, SC 
  4. Dallas, TX 
  5. Oklahoma City, OK 
  6. Tulsa, OK 
  7. Richmond, VA 
  8. Des Moines, IA 
  9. Raleigh, NC 
  10. Fayetteville, AR 
  11. Allentown, PA 
  12. Baton Rouge, LA 
  13. Sarasota, FL 
  14. Houston, TX 
  15. Columbia, SC 
  16. Orlando, FL 
  17. Little Rock, AR 
  18. Chattanooga, TN 
  19. Greensboro, NC 
  20. Kansas City, MO 

How to Prepare for the Future

Monitoring Pollen Counts & Air Quality Indexes

Keeping track of pollen counts and air quality indexes is essential when it comes to managing allergies and tracking the severity of allergy seasons. According the Asthma and Allergy Foundation of America, pollen counts are taken from samples of pollen gathered at monitoring sites and are based off actual data, while pollen forecasts. Reliable sources for pollen information include pollen forecasts and counts from the National Allergy Bureau (NAB), which is affiliated with the American Academy of Allergy, Asthma, & Immunology (AAAAI)There are also pollen activity calendars available on our website that outlines which pollens are most prominent by region and time of year. 

Tips for Reducing Allergen Exposure at Home and Outdoors

Tips for at home prevention: 

  • Use high-efficiency particulate air (HEPA) filters in the home 
  • Keep windows closed during high-pollen days 
  • Regularly clean the home to minimize dust mites, mold spores, and pet dander 
  • Maintain low humidity levels to prevent mold growth 

Tips for outdoor prevention: 

  • Avoid outdoor activities during peak pollen time by monitoring pollen counts and forecasts 
  • Wear protective wear such as sunglasses, face masks, or long clothing to protect from potential allergen exposure 
  • Shower and change clothes after spending time outdoors to remove pollen from the body 

Overview of Available Allergy Medications and Treatments

Several medications and treatments are available to alleviate allergy symptoms: 

  • Antihistamines 
  • Decongestants 
  • Nasal Corticosteroids 
  • Leukotriene Receptor Antagonists 
  • Allergy Immunotherapy, which HollisterStier Allergy provides for various allergens and stinging insect venom 

It is essential to understand the factors driving changes in allergy seasons and severity of symptoms so that proactive measures can be taken to mitigate allergic responses. Although some aspects are out of personal control, there are ways for healthcare professionals to inform and advocate for their patients now and in the future. 

Article References

1Schmidt, Charles W. “Pollen Overload: Seasonal Allergies in a Changing Climate.” Environmental Health Perspectives, vol. 124, no. 4, Apr. 2016, https://doi.org/10.1289/ehp.124-a70.

2D’Amato, Gennaro, et al. “Meteorological Conditions, Climate Change, New Emerging Factors, and Asthma and Related Allergic Disorders. A Statement of the World Allergy Organization.” World Allergy Organization Journal, vol. 8, 2015, p. 25, https://doi.org/10.1186/s40413-015-0073-0. 

3“Allergies: Overview.” Nih.gov, Institute for Quality and Efficiency in Health Care (IQWiG), 13 July 2017, www.ncbi.nlm.nih.gov/books/NBK447112/.

4Williams, Riis. “Seasonal Allergies May Be Getting Worse because of Climate Change.” Scientific American,.

5Zhang, Yong, et al. “Allergenic Pollen Season Variations in the Past Two Decades under Changing Climate in the United States.” Global Change Biology, vol. 21, no. 4, 7 Nov. 2014, pp. 1581–1589, https://doi.org/10.1111/gcb.12755. Accessed 3 Oct. 2021.

6Asthma and Allergy Foundation of America, (2024). 2024 Allergy Capitals. Retrieved from allergycapitals.com. 

7“AAAAI.” Pollen.aaaai.org, pollen.aaaai.org/#/. 

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