Scientists May Have Found the Reason Your Allergies Keep Getting Worse
New research shows that nerve cells "remember" allergens, and climate change is making the problem even bigger.
About 80 million Americans deal with seasonal allergies every year. These allergies cause sneezing, itchy eyes, and runny noses, especially in fall. Scientists have now found a big clue about why allergies develop — and why they can get worse over time. A new study suggests that certain nerve cells in the body actually remember the things that trigger allergic reactions, like pollen and mold.
Researchers at Mass General Brigham Health Care System led the study. They found that nerve cells — the cells that help us feel things like pain or an itch — can store memories of allergens. Even after the allergen is gone, these cells can react more strongly the next time they encounter something similar. This helps explain why people who are allergic to one thing often become sensitive to other allergens too.
The scientists tested their ideas on mice. They exposed the mice to allergens like dust mites and a compound made from papaya. After this exposure, the nerve cells started a special process that made them react to other allergens with a similar structure. The researchers believe the cells were recognizing a shared feature among different allergens. This could be why someone who is allergic to one type of pollen might also react to other types.
Dr. Caroline Sokol, a doctor and scientist at Mass General Brigham, explained why this discovery matters. She said that knowing what causes people to pick up more sensitivities means scientists can now design ways to stop it. The team also found that the allergic memory stored in nerve cells fades over time. Dr. Sokol said they are looking into ways to reset that memory, which could one day lower the risk of developing allergies.
Allergies happen when the immune system treats a harmless substance — like pollen — as if it were a threat. The body then overreacts, causing symptoms like sneezing and watery eyes. Pollen from trees, weeds, and grasses is one of the most common triggers. Each season brings different types of pollen, so symptoms can change throughout the year.
Climate change is making allergy season longer and harder to deal with. Warmer temperatures cause plants to bloom earlier and stay active later into fall. Freezing temperatures usually bring relief by killing off pollen, but those freezes are arriving later than before. According to Climate Central, nearly 180 U.S. cities now see their first freeze about 12 days later than they did in the early 1970s.
This fall, a strong El Niño weather pattern made things even worse in some areas. El Niño brought extra wet conditions to the Southeast and southern Rocky Mountain regions, and forecasters say wet weather raises pollen levels. So people in those areas faced a harder allergy season than usual. Even so, scientists say this new research gives hope that better treatments are on the way.
"Now that we know what may cause people to become allergic and pick up more sensitivities, we can design ways to stop it from happening."
Comprehension quiz preview
1. How many Americans are affected by seasonal allergies, according to the article?
2. What does the word 'allergen' mean as used in this article?
3. Why might someone who is allergic to one type of pollen also react to other allergens?