What is an Allergen?

Every fall, more than 35 million Americans suffer the unwanted return of the burning eyes, sniffles, chapped nostrils and stifled lungs of allergic rhinitis, or hay fever. If you're one of them, the following are answers to some frequently asked questions that can help stop the misery.

Q: What is an allergen?
A: Any substance, such as pollen, mold or animal dander that can trigger an allergic response.

Q: What are common symptoms?
A: Watery eyes, sneezing, a runny nose, itchy eyes and nose

Q: What is allergic rhinitis or hay fever?
A: Allergic rhinitis, which is often called hay fever, is the body's immune system overreacting when it comes into contact with certain allergens such as pollen or mold. When people with allergies inhale these substances, an allergic antibody dubbed IgE treats them like dangerous invaders and gloms onto them. This triggers the release of histamines and other chemicals, which cause the trademark allergic response of sneezing, dripping nose, congestion and itchiness.

Q: How can you distinguish between hay fever and the common cold?
A: While watery eyes, sneezing, runny nose and itchy eyes and nose are common to both, a cold can also cause fever and aches and pains. And allergic symptoms last as long as you are exposed to the allergen and beyond, while a cold should clear up within several days to a week.

Q: What's the best way to avoid fall allergies?
A: The best way to cope with fall allergies is to avoid pollens. That usually means staying inside during the peak pollen periods - the early morning and late afternoon hours.

You should also shut the windows and crank up the air conditioner in both your house and car. That will help prevent pollens from drifting into your home.

Apply the same reasoning to your laundry: best to use the dryer so any allergens can be filtered out instead of hanging it on the line, where it becomes the filter.

Also, think about taking a vacation to a more pollen-free area, such as the beach or sea. And don't mow lawns or be around freshly cut grass; mowing stirs up pollens and molds.

Q: What medications are used to treat allergies?
A: Antihistamines are used to prevent or relieve the symptoms of allergic rhinitis and other allergies. They work by preventing the production of histamine, a substance produced by the body during an allergic reaction.

Decongestants are used to treat nasal congestion and other symptoms associated with colds and allergies. They work by narrowing blood vessels, leading to the clearing of nasal congestion. Steroid nasal sprays reduce nasal inflammation and the accompanying congestion, sneezing and runny nose.

This feature was edited by Stuart A. Friedman, MD, FAAAAI, AAAAI Patients & Consumers Web Editor on 3/18/04.