Tim Tai, Photography Editor

On March 20, spring officially began, promising an uptick in squirrel sightings and a sharp decline in puffer jackets on campus. However, for those with seasonal allergies, the new season also brings runny noses, sneezing and congestion. 

Seasonal allergies result from the immune system overreacting to a certain environmental allergen, such as pollen, mold spores or dust mites. In the spring, the main culprit is an increase in pollen. When one of these allergens is inhaled or comes in contact with the eyes or nose, the body triggers an immune response. Specialized cells in the immune system mount defenses, releasing histamine — a compound that is responsible for various allergy symptoms — and other chemicals. 

“You can have allergies to basically any type of pollen, and they tend to be the kind that are small and carried by the wind, and people can be allergic to tree pollens, grass pollens [and] pollens from weeds,” said Elise Liu, associate research scientist in immunology and instructor in rheumatology at the Yale School of Medicine.

Florence Hsu, assistant professor of clinical medicine in allergy and immunology at YSM, explained that histamine and other chemicals entering the bloodstream causes blood vessels to dilate and “leak,” leading to nasal congestion and runny nose. Other effects include sneezing, itching and allergic inflammation. Afterwards, the immune system produces antibodies — proteins produced to counteract a specific antigen or foreign substance — which initiates an immune response. 

These antibodies bind to the allergen and activate other immune cells, further contributing to the immune response and thus to the gravity of symptoms. In addition, repeated exposure to allergens can cause the immune system to become increasingly sensitive to them, producing more severe and prolonged symptoms with every additional exposure. 

“When people have allergies, they typically have symptoms that affect their nose and their eyes,” Liu said. “You can have a runny nose, congestion and post nasal drip that can lead to sore throat sometimes. For the eyes, people can often get itchy, watery red eyes.”

Additionally, Liu and Hsu both noted that some people with seasonal allergies are prone to developing oral allergy syndrome — a type of food allergy. 

Oral allergy syndrome occurs when the immune system reacts to proteins from a food that are similar to those found in pollen. 

“The proteins in the pollen look very much like proteins in certain fresh fruits and vegetables, so … when people eat those fresh fruits and vegetables, the allergic antibody against the pollen actually reacts against the proteins in their fruits and vegetables,” Liu said. “The immune response to these fruit proteins can lead to itching, discomfort and sometimes swelling.”

According to Hsu, however, there are ways around this, since most people who have this allergy can eat cooked forms of the fruit “perfectly fine” without experiencing symptoms.

To counteract seasonal allergy symptoms, Liu said that there are medications and lifestyle changes that can be implemented. 

“It can be really helpful to change out of the clothes that you’re wearing outside to shower or wash your face, at least to get rid of all the pollen particles that are stuck on you from outside,” Liu said.

In regards to medications, Hsu noted that many antihistamines are available over-the-counter. In addition to antihistamines, she said that other medical treatments include nasal steroid sprays, inhalers for those with asthma and antihistamine eye drops.  

However, the struggles of people with seasonal allergies will likely increase in future years due to climate change. 

“Because of climate change and warmer temperatures, the allergy seasons have gotten longer and more intense,” said Keneth Mendez, president and chief executive officer of The Asthma and Allergy Foundation of America.

According to Mendez, the length of the allergy season has “more than doubled in length” since the 1980s. Moreover, carbon dioxide that is released from emissions helps fuel pollen releases in plants, which makes the pollen releases “more intense.”

An increase in pollen, he said, means that there are more allergens and as a result worse symptoms for those who have seasonal allergies. This can also introduce symptoms in people who previously were “unaffected by seasonal allergies.”

Seasonal allergies were first described by John Bostock in 1819.