For many people, cooler temperatures, colorful leaves and college football all signal the arrival of autumn. For approximately 36 million people in the United States, sneezing, itching and congestion serve as another notice that fall has arrived.

Allergies, or “allergic rhinitis,” is caused by inflammation and swelling in the nose and sinuses due to an allergy to non-infectious particles such as plant pollens, molds, dust mites and animal hair. Two types of allergic rhinitis exist — perennial allergic rhinitis and seasonal allergic rhinitis. Perennial allergic rhinitis is allergic rhinitis that lasts throughout the year, typically caused by continuous exposure to allergens such as animal dander, indoor mold spores, or house dust mites. Seasonal allergic rhinitis is allergic rhinitis that occurs only during certain times of the year and is commonly caused by allergies to seasonally produced tree, grass and weed pollen.

“If you have symptoms less than four days a week for four weeks a year, you have seasonal allergic rhinitis,” says Sandra Gawchik, D.O., co-chief of the Division of Allergy and Immunology at Crozer-Chester Medical Center. “If symptoms are more than that, you have perennial allergic rhinitis.” In many cases, patients with perennial allergic rhinitis will also suffer seasonal flare-ups.

Ragweed

In the fall, ragweed triggers a significant amount of seasonal allergy sufferers’ allergic reactions. Ragweed flowers mature and start releasing pollen in mid-August. During the one-season lifespan of a ragweed plant, over one billion grains of pollen are produced. This number can vary depending on how much rain fell over the summer.

“Rainfall during the summer affects the ragweed plant’s root system growth and pollen production,” says Thomas Klein, M.D., chief of the Section of Allergy and Immunology at Delaware County Memorial Hospital. “The more summer rain there is, the more ragweed pollen there will be in the fall.”

Ragweed pollen, which typically is found along roadsides, in vacant lots, fields and generally sunny spots, can travel up to 400 miles from its origin. Heat, humidity and breezes all aide in dispersing the pollen, which can land on a person’s clothes, hair and in through house windows.

“While the classic fall allergen is ragweed, patients will also often be allergic to mold, which will be a problem until the ground freezes,” says Anthony Rooklin, M.D., co-chief of the Division of Allergy and Immunology at Crozer-Chester Medical Center. “Dust mites also become a problem indoors especially when the house closes up before the heat goes on and dries everything out.”

Symptoms

While most symptoms from allergies to ragweed and other irritants are not severe, they can be very inconvenient, and resulted in a collective two million school days missed last year by children suffering from allergies.

“A stuffy nose is the most severe thing people usually complain about,” Gawchik says. “People also typically have itchy eyes, and if these symptoms continue, they can lead to congestion, which can affect a person’s sleep at night. If the symptoms reach a point where they affect sleep, the person should visit their local allergist — 12 percent of people with untreated allergic rhinitis go on to develop asthma.”

Prevention

For allergy sufferers, prevention is key. While not all symptoms are avoidable, a person may lessen the severity of the symptoms to make the season more bearable by following some physician-recommended tips:

• Use air conditioning to stay cool. Fans stir up dust mites in the home and open windows allow pollen to pass into the house.
• After periods of time spent outdoors, shower and wash hair immediately upon returning to the house to get rid of pollen that may have attached itself to hair or skin.
• Avoid drying clothes outdoors, as pollen can attach to clothes.
• If you have pets, brush their hair regularly and keep them from entering into the bedroom.
• Keep car windows closed while driving, which will prevent pollen from entering into the car.
• Use an indoor air purifier inside the home, which helps to decrease pollen counts as well as mold, dust mites and pet dander concentration.

Medications can help alleviate allergy symptoms should none of the above tips help to deter the onset of a reaction.

“Nasal steroids, available by prescription only, and non-sedating antihistamines will help many patients control symptoms,” Rooklin says. “Immunotherapy, also known as allergy shots, is also very helpful when medication isn’t enough.”

“Over-the-counter medications, like Claritin, often work well for people,” Gawchik says.

Klein, Rooklin and Gawchik all recommend contacting an allergist should over-the-counter medications and preventative measures not help to lessen allergic reactions.