First a sneeze and a sniffle, then a coughing fit on your drive to work. Now a runny nose and watery eyes as you sit in your office. What’s going on? You’re suddenly showing all the signs of … allergies?

Sometimes allergies begin when you’re an adult. It’s called adult-onset allergy.

How does it happen? James Sublett, MD, with the American College of Allergy, Asthma & Immunology (ACAAI), suggested to The Wall Street Journal that exposure to pollution, poor indoor air in a new home or workplace, or adopting a new pet are factors that could lead to symptoms you’ve never had before.

“There are even some viruses that can trigger allergies,” including the common cold, Dr. Sublett said. In addition, as people age their immune system might become more sensitized, opening the door to new allergies.

Perhaps you’re wondering if you’re developing allergies? ACAAI’s telltale signs include:

— Symptoms for two weeks or more? If yes, it’s likely allergies.

— Are symptoms evolving? If you started with a sore throat and it evolved to a runny nose, it’s likely a cold.

— Wheezing or itchy eyes, nose or throat? If yes, it’s likely allergies.

Make an appointment with your doctor to find out for sure. You may be referred to a board-certified allergist who can help you identify what’s causing your allergy symptoms and develop a treatment plan.