If you’ve been itchy, struggling to breathe through your nose and had a swollen, sore throat, there may be one seasonal culprit: ragweed.

More: This Is Nashville’s ‘Allergy season in Middle Tennessee’

About 50 million Americans have some kind of allergy to the plant’s pollen, which starts spreading in the late summer and early fall.

Nashville’s overall pollen count passed into the highest count range on Aug. 23, according to Pollen.com. Several local governments use that data in air quality reports, including Metro Nashville. Virtually every day since then has seen maxed out pollen counts.

WPLN talked with Dr. Cosby Stone, an associate professor at Vanderbilt University Medical School. He works in the allergy, pulmonary and critical care division.

Why are fall allergies so bad here?

There are a few factors, but big ones are weather, traffic and geography.

“The plants can release billions of pollen grains per plant — and especially if it’s been hot and especially if there’s a lot of carbon dioxide in the air,” Stone said. “You know, like next to a roadway, that ragweed plant will release a lot of pollen. Ragweed actually is one of the few plants that’s sort of taking advantage of pollution, unfortunately.”

Middle Tennessee sits in the state’s Central Basin — otherwise known as the Nashville Basin. It’s a lower elevation, surrounded by the Highland Rim and the Cumberland Plateau.

“We’re down in a bowl,” Stone said. “A lot of the carbon dioxide sort of collects down in this bowl along with the heat, and the ragweed loves it.”

All-over itchiness

“The approach that I like to take is to use over-the-counter antihistamine tablets,” Stone said. “And it doesn’t have to be the older generation antihistamine tablets like Benadryl, you know, that make people sleepy — especially because those things only last about 4 to 6 hours. So I tend to think more of the 24-hour relief, that you get from a non-sedating antihistamine, the newer generation stuff.”

Itchy eyes

Regular eye drops will help dry eyes, but Stone says you can now buy some specifically for allergy symptoms.

“There are antihistamine eyedrops that are over the counter now, and they work really well,” he said. “We used to prescribe them all the time.”

They reduce inflammation and itchiness, and they work quickly because they’re being applied directly to the affected area.

Swollen nose

If you’re trying to blow a stuffy nose, but nothing comes out, your nasal cavity might be empty but inflamed.

“People will often get swelling in their nose, so they find that it’s hard to breathe at nighttime,” Stone said. “The ingredient that helps the best with nasal swelling — if that’s the main problem that you’re up against — it’s going to be something like an inhaled nasal steroid.”

There are prescription sprays, but you can also get them over the counter at the drug store.