You're sniffling and sneezing again. You're feeling tired and headachy again.
Perhaps it's not your third (or fourth or fifth) cold of the season, but an allergy. Most people don't consider allergies the cause of their coldlike symptoms in the winter, because the cause of most respiratory allergies — pollen — is usually not drifting about in cold and snowy climes.
Yet some of the most common allergies are to indoor things: Dust mites, mold and animal dander top the list. And in the winter, we tend to spend more time indoors with these potential triggers.
Allergies are overreactions of the immune system to foreign particles that should be innocuous. For reasons that scientists don't fully understand, some people react to dust mites or mold spores as if it they were a pathogen. There's an antibody response and an inflammatory cascade of events that leads to the classic symptoms — itchy eyes, runny nose and sneezing — says allergist Jackie Eghrari-Sabet, founder of Family Allergy and Asthma Care in Gaithersburg, Md. Sometimes the congestion is bad enough to cause sinus pressure and headaches.
But how do you know which is which — if you have an allergy or a cold? While they are caused by different things, both a virus and an allergen set off your body's immune responses. That's why symptoms overlap — a runny or stuffy nose, a cough and sore throat, and fatigue. Some symptoms are more likely to occur with allergies, such as itchiness of the eyes, ears and back of the throat. Other symptoms, such as aches and fever, indicate a viral infection.
Another key difference is the course and persistence of symptoms. "With a cold, first you feel crummy, then you're sick and then gradually your symptoms go away," says Joan Lehach, an integrative medicine physician specializing in allergy and asthma at Montefiore Medical Center in New York. With a cold, she says, this sequence may last a week or so. "Allergies last longer."