Doctors say this spring may be one of the worst allergy seasons we've seen yet.

Doctors say it all comes down to climate change - and that this allergy season may be three weeks longer.

Dr. Phil Hemmers, division chief for allergy and immunology with Hartford HealthCare St. Vincent's Medical Center, says we have higher pollen levels due to factors such as environmental trends, climate change and more warmth.

"We're already transitioning this week to moderate range for tree pollen. Things like birch, maple, elm ... those numbers are already high. They'll continue to be high," says Hemmers.

Hemmers says allergies can start at any age. The Centers for Disease Control and Prevention says more than a quarter of adults and about 1 in 5 children experience seasonal allergies in the United States. Allergy symptoms include sneezing, a runny nose and itchy watery eyes.

There are steps you can take to reduce your risk of allergies.

"Don't bring that pollen in with you. Keep the windows closed in our car, in your house, use the air conditioner, take a shower, get all of that pollen off of you," says Hemmers.

Doctors say there are a number of good over-the-counter oral medications and nose sprays you can use. You can always see an allergist if things get worse.

Current estimates put pollen-related medical expenses at more than $3 billion annually.