With the approach of springtime, most Americans will gladly trade in snowy, icy weather for milder temperatures. But as the days grow longer, the budding trees and blooming flowers are also bearers of an unpleasant reality: allergy season.

And if you're one of the tens of millions of Americans with seasonal allergies, experts say you may have to cope with your symptoms longer because of the effects of climate change.

For Michelle Ehrman, relief from her allergy symptoms seems elusive.

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"I just get this lingering cough. I've been on inhalers, been put on nose sprays and then I've been getting these shots on top of it," she told CBS News.

Experts say symptoms for allergy sufferers like Ehrman might only get worse over time, because rising temperatures from climate change and more carbon dioxide in the air are causing many pollen-producing plants to bloom earlier – and last longer – thus prolonging allergy season.

Dr. Joseph Shapiro, an allergist and immunologist in Los Angeles, says his office is now flooded with patients year round.

"New patient visits are coming in at different times of year that I did not use to see," he said.

According to the Centers for Disease Control and Prevention, more than 50 million Americans suffer from allergies each year. While allergies are more common in children, they can occur for the first time at any age.

With allergy seasons growing longer and more intense, experts say many people are developing seasonal allergies for the first time well into their adulthood.

Shapiro said many of his patients' symptoms are more severe than in the past, and he expects the trend to continue, as well.

"A recent study showed that pollen counts are likely to double by the year 2040, so in a little more than 20 years we're going to see a significant increase," he said.

Allergists say early spring is the critical time to start your seasonal allergy medications. Often people wait until the season is well underway to take their medications, but by then their symptoms are already severe.

Ehrman recently started on allergy shots and thinks they may be doing the trick.

"We've been doing about three a week," she said.

These injections contain some or all of the allergens causing a patient's problems. Gradually, the injections get stronger, and over time, symptoms lessen. Talk to your doctor about possible allergy treatments that are right for you.