HEALTH TOPICS 
Ask the doctors
Q. I feel like I have a perpetual cold all winter, every winter. I'm stuffy and sneezy and it never seems to get better. Do you think it could be allergies? How can I tell the difference?
A. Colds and allergies produce many of the same symptoms: a runny nose, tiredness, and sometimes a sore throat. But they have different causes — a virus causes colds, while allergies are an immune system response to trigger substances, known as allergens. There are ways to distinguish one from the other. Colds sometimes produce a fever, but allergies never do. In addition, if you are suffering from allergies, you may also have itchy, watery eyes, symptoms that won't typically accompany a cold. But perhaps the biggest clue that can help you distinguish between a cold and allergies is the duration of symptoms. Cold symptoms rarely last more than two weeks, but allergies can last as long as you are exposed to the substance that is triggering the reaction. So, if your "cold symptoms" appear at the same time every year and last for an extended period of time, the cause may very well be allergies. Many people with seasonal allergies will experience symptoms for six weeks at a time. If you are allergic to something in your home, such as dust mites, mold, or pet dander, your symptoms could get worse during the winter months, because the house is sealed up and fresh air isn't getting in. In addition, your heating system may be recirculating the allergen. Because your symptoms last for an extended period of time, it may be worth a visit to the allergist.
— by Hope Ricciotti, M.D., and Hye-Chun Hur, M.D., M.P.H.
Editors in Chief, Harvard Women's Health Watch