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The Medical Minute: What causes seasonal allergies, and how to alleviate the symptoms

Welcoming spring this year, even after a long cold winter, has been bittersweet for the millions of allergy sufferers already experiencing itchy eyes, nasal congestion, sneezing and a runny nose.

What causes someone to be allergic to seasonal allergens and other irritants is unknown. The key to understanding allergies may lie in genetic and environmental triggers as well as a person’s lifestyle.

According to Dr. Timothy Craig, Division of Allergy, Asthma and Immunology at Penn State Hershey, there are many variables that can cause a person to be predisposed to allergies.

“It's not like some diseases that are just based on one gene; it's definitely multiple genes combined with the environment,” Craig says.

Family history of allergies and asthma can predispose people to suffer from allergies. A person's overall health can contribute to susceptibility as well, as do lack of exercise, obesity and poor diet.

Environmental concerns like early exposure to second-hand smoke can make a person vulnerable to irritants. Spending too much time indoors, not being exposed to pets and other animals and not being exposed to enough bacteria and viruses can also contribute to allergies.

Known as the hygiene hypothesis–being too clean and compromising the adequate development of the immune system–Craig says it increases susceptibility to allergies because a person has not built up a tolerance to irritants.

Antibiotics and vaccines, while protecting us from dangerous and serious diseases, have also weakened our resistance to allergies and asthma, he says.

“Predisposition combined with all the Westernized changes we have, like decreased infections thanks to vaccines, is what probably helps determine our chances of acquiring allergies,” he said.

Additionally, Craig awaits the findings from current studies that suggest there is a direct link between vitamin D deficiency and the ability to fight allergens and asthma because it plays a role in regulating the immune system.

When exposed to an irritant like tree pollen, a sensitized person's mast cells–part of the immune system and located throughout the body–rapidly release histamine in defense. Histamine is a chemical response to the allergen and is what causes allergy symptoms.

Some people eventually build up a tolerance when exposed to an allergen on a regular basis. If the allergen is removed, a person can become hypersensitive when they come in contact with it again. This is often seen when students who are allergic to cats and have a cat in the home leave to attend college, then return to the home and develop severe symptoms.

The most common allergen this time of year is tree pollen. This year, the trees are expected to bloom rather quickly with the rapid acceleration of temperature causing excessive amounts of pollen. To learn more about why this season is expected to be so bad for allergy sufferers, watch this short video with Dr. Faoud Ishmael.

To combat and lessen seasonal allergy symptoms:

  • Shower at the end of the day to remove pollen from your hair and body.
  • Wash your clothing promptly.
  • Rinse your nose with saline before bed to remove debris.

Craig also advises that eating properly and getting enough sleep can help fight the results of allergies that cause fatigue or ill feelings. He also advises to exercise regularly. While that may sound strange, there have been studies showing that physical activity can decrease allergic reactions. It is also best to avoid outdoor activity in the late afternoon when winds usually pick up and circulate more pollen.

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The Medical Minute is a weekly health news feature brought to you by Penn State Milton S. Hershey Medical Center. Articles feature the expertise of Penn State Hershey faculty physicians and staff, and are designed to offer timely, relevant health information of interest to a broad audience.

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