Spring is an exciting time when it brings liveliness to nature; however, it also releases countless pollen grains into the air. Pollen is critical to the survival of many plant species, but it is also a common trigger of seasonal allergies (also called hay fever or allergic rhinitis). In humans, the immune system can react to pollen as a harmful invader when it enters the body through the nose or mouth. Some bothersome symptoms of seasonal allergies include sneezing, coughing, watery eyes, and running nose. This article will discuss the trends in allergy season and provide you with some more knowledge about seasonal allergies and how to manage symptoms.

Trends in allergy season

If you are one of the 81 million people in the United States (U.S.) who have been diagnosed with seasonal allergies or who are managing allergies independently, you may already be aware that allergy season is starting earlier, and allergy symptoms are worsening. According to the World Allergy Organization (WAO), the prevalence of allergic diseases has been increasing over the past few decades and there may be several contributing factors.

One theory is that the warmer temperatures attributed to climate change may modify pollen seasons by increasing the amount of pollen produced in spring or extending the duration of pollen season in fall. These changes can affect the intensity of symptoms or the duration of allergy season. The results from the Proceedings of National Academy of Science (PNAS) further support this finding through data showing that climate change has worsened pollen seasons over the past 30 years. PNAS found an extension of pollen season by 20 days and an increase in pollen concentration by 21% in 2021. The investigators are concerned that the climate-driven pollen trends are likely to continue to worsen lung health in coming decades.

While it is important to note that allergies are becoming more common in some parts of the world, this may not be the case in all regions. A research team studying pollen measures in the U.S. between 1994 and 2010 reported that the further you live away from the equator, the longer the pollen season. The data was gathered from weather stations across the U.S., excluding Alaska and Hawaii. Researchers found the timing of pollen season was likely related to temperature and rainfall in the north-eastern climate regions. When a region becomes warmer and wetter, it favors more growth of plants, increasing pollen production in the area. Therefore, changes in allergy season may differ by location and are influenced by multiple factors.

In conclusion, there is evidence to suggest seasonal allergies are becoming more common and severe in the U.S.; however, the exact cause is still unknown. It is important for people who suffer from allergies to work with their healthcare providers to identify the specific allergen and develop a management plan to minimize the impact of allergies on quality of life.

Managing allergy symptoms

There are many weather apps and websites that provide daily pollen updates so you can be prepared for symptoms on days of higher pollen count. Symptoms of seasonal allergies can also be managed with medications that do not require a prescription. See our previous article for an overview of these options. A few things to keep in mind for these medications are the side effects and time to action, as they vary slightly from one another. For example, most oral antihistamines (i.e., Zyrtec, Claritin) are fast-acting, but nasal sprays (i.e., Flonase), may take several days for maximal effect.

Need help deciding on a medication? Ask your local pharmacist for recommendation! Pharmacists are trained professionals in medication use, one of your most accessible healthcare providers, and ready to help you find what works best for you.


Prepared by Emily Hsieh, PharmD Candidate 2023


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