Each year, 40 million Americans suffer from seasonal allergies, when airborne irritants trigger an overreaction of the immune system, marked by itchy, watery eyes, violent sneezing, coughing, wheezing, severe nasal or sinus congestion and, in some cases, difficulty breathing.

According to research firm IBISWorld, the average allergy sufferer in the U.S. spends an estimated $83 a year on over-the-counter allergy medications, which works out to $3.3 billion annually nationwide.

It turns out that whether and how much you suffer may hinge on where you call home.

For the tenth consecutive year, non-profit patient organization the Asthma and Allergy Foundation of America (AAFA) has released its list of the worst cities for allergies in the nation. Researchers analyzed the 100 largest metro areas in the U.S. by three factors: pollen levels in each city, counted by Pollen.com; 2011 retail sales of prescription and over-the-counter allergy medicines (including eye drops, pills and nasal sprays) per allergy patient, provided by IMS Health; and the number of board certified allergists and immunologists per patient, as tracked by the American Board of Medical Specialties.

Topping the list, Knoxville, Tenn., is the worst city for allergies in the U.S. for the third year in a row. Knoxville features some of the country’s highest pollen levels, with well over 300 grains of pollen per cubic meter of air daily—sending many a citizen to the local drug store. Allergy sufferers there purchase more than two medications each, well above the national average of one per patient.

Residents of Tennessee are really feeling the itch this year. Chattanooga, Tenn., ranked as the seventh worst allergy city, after its placement at No. 5 last year, and Memphis, Tenn., jumped to No. 8 this season, from No. 17 in 2011.

“The South experienced a very mild winter,” says Dr. Rana Bonds, assistant professor of allergy and immunology at The University of Texas Medical Branch in Galveston, Tex. “Warmer weather meant spring started earlier, and the pollen came out with a vengeance.”

A typical spring allergy season spans from March to May, when the trees begin to pollinate. Dr. Bonds says this year pollen began spiking in early February, which will result in an especially long spring allergy season with a high number of irritants. Later in the year, other allergens come out, including grass pollen in the summer and weed pollen in the fall.

Cities in the South, like Louisville, Ky., at No. 3 this year, frequently rank in the top of the list due to warmer climates, extended seasons and local vegetation. Dr. Bonds says some trees produce more pollen than average, like oak, elm, maple and mountain cedar, the latter of which is more often found in the South than the West coast or Northeast.

Many a Texan may also suffer sneezing attacks this year. McAllen, Tex., ranked as the second worst allergy city, and San Antonio, Tex., leapt 33 spots to land at No. 9. The state has experienced a prolonged drought, which Dr. Bonds believes may contribute to especially high pollen levels this year. “The survival mechanism of the trees is to produce more pollen after a drought because they think they aren’t going to make it,” she explains.

The top five best cities for allergies in 2012 are Portland, Ore. (No. 100); Boise City, Idaho (No. 99); Daytona Beach, Fla. (No. 98); Denver, Colo. (No. 97); and Salt Lake City, Utah (No. 96).

No matter where you are this year, allergists offer some helpful tips to prevent or get relief from spring hay fever. “The best thing to do is get tested and find out what you’re allergic to,” says Beth Corn, director of the Allergy/Asthma Clinic in New York’s Mount Sinai Medical Center. Generally, she suggests trying an antihistamine, eye drops and a saline wash to rinse your nasal passages. She also recommends avoiding outdoor activity between 10 a.m. and 2 p.m., the height of pollen production. When returning from the outside, change clothes and wash off.

Inside the home, experts at the AAFA suggest keeping surfaces clean and uncluttered, washing bedding weekly with water above 131 degrees F. to kill mites and their eggs, and using zippered allergen barriers or “encasements” on all pillows, mattresses and box springs. While bare floors are best, if you have carpet, vacuum one to two times a week to keep allergens to a minimum. A dust mask should be worn while cleaning, and a HEPA air filter helps to remove irritants from the air.

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By Jenna Goudreau
April 13, 2012
Forbes.com