You’ve sailed through life unbothered by those pesky allergies that leave other people complaining about their runny noses and itchy eyes. Now you’re one of them, with the crumpled tissues to prove it. Whether the trigger is the invisible billows of tree pollen or your new cat, you’ve got all the classic signs: a runny, itchy, congested nose and itchy, watery, red eyes.

Turns out developing a seasonal or respiratory allergy isn’t just for kids. About 20 million adults deal with hay fever symptoms, according to the Asthma and Allergy Foundation of America. And there’s some proof that as allergy rates rise in the U.S., more adults are getting them for the first time. A 2016 Rutgers University study found that between the mid-1970s and mid-1990s, the number of Americans who reported classic allergy signs tripled. Currently, those numbers do not appear to be reversing course.

What causes adult-onset allergies?

No matter how old you are, when allergies strike, the basic process is the same: You’re exposed to something such as tree pollen or dog dander. Your body mistakenly thinks this harmless substance is an invader, and your blood starts producing a specific kind of antibody known as immunoglobulin E (IgE). These IgE antibodies hang out in certain areas, such as your airways, eyes and skin. The next time you cross paths with the allergen, your body overreacts and goes on the attack. Your runny nose, swollen sinuses and sneeze attacks are the result.

Why are you experiencing these lovely symptoms now? There are a few possible reasons, says Sakina Bajowala, MD, medical director of Kaneland Allergy and Asthma Center in North Aurora, Illinois.

Moving to a new area. You may have always been sensitive to a certain tree pollen. But perhaps that tree doesn’t grow where you used to live. Simply being around new grasses, trees or molds could set off a problem.

Workplace issues. You could have a reaction if your job exposes you to animals, plants or mold. Some people also notice a problem with latex if they have to wear the gloves at work.

Spending more time indoors. You may breathe in more mold, pet dander and dust when you’re inside a lot.

Reduced tolerance. Tolerance for all sorts of allergens may go down as you age. But experts don’t fully understand why. “Low-grade respiratory allergies can worsen over the years until they become troublesome enough to need medication,” says Dr. Bajowala. This can also happen temporarily during pregnancy, when some women’s allergies get better or worse. If you’re pregnant, talk with your doctor before using any allergy medications.

A new pet. Welcoming home a new pet can set off symptoms. Surprisingly, so can returning home to an existing pet after you’ve been out of the house for a few days or longer.

More intense pollen seasons. Since 1990, pollen seasons in the U.S. have gotten longer by an average of 20 days, according to a University of Wisconsin Madison study. And the air is filled with 21% more pollen. The cause? Researchers pointed to climate change.

An Expert Plan for Treatment

Now you’ve got some sense of why you have allergies. But what can you do to feel better? The first step is to see a board-certified allergist. Getting tested will pinpoint the exact cause or causes of your symptoms. You and your doctor can then develop a plan just for you. It might look something like this:

Sidestep triggers. Do what you can to stay away from what’s provoking your symptoms. This could mean keeping the windows shut and running the air conditioner to keep pollen out.

Reach for a steroid nasal spray first. That’s the recommendation in the most recent guidelines from the American Academy of Allergy, Asthma and Immunology (AAAAI) and the American College of Allergy, Asthma and Immunology (ACAAI). Nasal sprays have been shown in studies to work better than antihistamine allergy pills for relieving nasal allergy symptoms. Use one every day during pollen season.

It may take a few days or even weeks to get the full congestion-relieving benefits, Dr. Bajowala notes. For best results, if possible, start using one before your allergy season begins. (A good note for next year!) Steroid nasal sprays include:

  • Budesonide (Rhinocort®)
  • Fluticasonefuroate (Flonase® Sensimist) and fluticasone propionate (Flonase®)
  • Mometasone (Nasonex®)

Did you know that different pharmacies charge different prices for the same prescriptions? Find the best deal on allergy medicine near you with the Optum Perks app.

Add an antihistamine nasal spray if needed. Antihistamine nose sprays can take care of sneezing and a runny nose, and they may help with stuffiness too. Use one along with a nasal steroid if the antihistamine spray alone isn’t working well enough, the AAAAI/ACAAI recommends. Spray options include:

Try antihistamine pills for quick help. Oral antihistamines are a good choice for mild symptoms, Dr. Bajowala says. Just be sure to choose newer antihistamines instead of “first generation” ones, such as Benadryl, which can make you feel tired and cause dry mouth, constipation, rapid heartbeats and lead to difficulty urinating. Newer antihistamines include:

Ease your eyes with drops. If your eyes are the only issue, drops may do the trick, Dr. Bajowala says. Or you can use drops along with other medications, if you need more help. Options include:

  • Azelastine (Optivar®)
  • Bepotastine (Bepreve®)
  • Ketotifen(Alaway®, Zaditor®)
  • Olopatadine(Pataday®, Patanol®)

Be careful with decongestants. Decongestant nasal sprays and pills work by shrinking nasal swelling, which can make you feel better but can also cause longer-term problems. “Certain oral decongestants can raise heart rate and may not be safe for people with high blood pressure,” Dr. Bajowala says.  Talk to your doctor or pharmacist to find out which one is right for you.

Decongestant eye drops can be problematic too, with side effects including eye redness and swelling; increased itching of the eyes; headaches; a stuffy or runny nose; and/or a sore throat.