Your New Allergy Survival Guide

Every year, sneeze sufferers swear: "This is the worst allergy season ever." And they’re right. "Pollen levels are increasing, pollen seasons are getting longer, and more people are developing allergies," says Estelle Levetin, PhD, chairwoman of the aerobiology committee for the American Academy of Allergy, Asthma & Immunology.

In the United States, nearly 8% of adults 18 and over suffer from seasonal allergies—that's nearly 18 million people.

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While spring and fall allergies cause the same symptoms (sneezing, itchy eyes, and runny nose), their triggers are different.

Spring allergies, which run from February to late July, are brought on by pollen from trees, grasses, and weeds. Fall allergies go from mid-August through the first autumn frost, and are chiefly set off by pollen from the ragweed plant, mold, and dust mites.

Read on to learn what’s making both seasons so unbearable—and the best ways to survive them.

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Spring allergies now start sooner and fall allergies end later, thanks to global warming, says Jeffrey G. Demain, MD, director of the Allergy, Asthma & Immunology Center of Alaska.

We’re using more carbon-based fuels, generating greenhouse gases that trap heat from the sun in our atmosphere. This makes temperatures rise, prompting plants and trees to flower—and release pollen—earlier each spring; in the fall, they delay the death of ragweed plants from frost, extending the pollen season, explains Levetin.

End result: "Fall" allergies may go practically into winter.

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Higher amounts of carbon dioxide not only kick-start pollen production, they also boost the amount of pollen each plant generates, too—especially in urban areas, where the gas is more plentiful. To add insult to injury, CO2 is making pollen more potent, too.

"There’s more allergen now in each grain than there used to be," Dr. Demain says. And pollen isn’t the only allergen on the rise. Increasingly balmy temperatures mean more moisture in the air, which creates mold.

"The higher temperatures and gas may increase not just the growth of mold but also its spore production—which is how it distributes allergens—both indoors and out," Dr. Demain says.

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The number of Americans with allergies is two to five times higher now than it was about 30 years ago, according to surveys from the National Institutes of Health.

Genes play a role in your susceptibility, but the blooming allergy boom is most likely due to the longer, more intense pollen seasons.

There are other expert-supported theories as well.

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Now that we’re exposed to less dirt and bacteria (thanks in part to our obsession with antibacterial everything), and have fewer scourges like polio and parasites to fight, our immune systems are quicker to overreact to otherwise harmless substances like pollen, says Levetin.

At the same time, our environment is too dirty: Studies show that pollution (such as exhaust fumes) can trigger allergic flare-ups.

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Today’s processed, preserved foods lack the tough fibers of the plants and grains our ancestors feasted on, throwing off the delicate balance of bacteria in our guts and setting us up for allergic sensitivity, says University of Michigan professor of internal medicine Gary Huffnagle, PhD.

Studies suggest, too, that as use of antibiotics—which also disrupt bacteria in the gastrointestinal tract—has surged, so have allergies.

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