Cold or allergy symptoms?

Unfortunately, you can’t always know for certain whether you’ve got a cold or an allergy; the two share symptoms: sneezing, runny nose, congestion and fatigue. While colds are caused by hundreds of different viruses, allergies are triggered by harmless substances, like ragweed, pollen, or cat dander, that your body mistakes for a threatening invader.

In either case, symptoms result from your immune system’s response to the interloper; the release of the chemical histamine, for example, causes your sinuses to swell, your nose to run, and sneezing.

Colds last only one to two weeks, commonly cause cough, sore throat and sometimes body aches and fever, but not itchy, watery eyes. Allergies can last for a month or more, commonly cause itchy eyes, and don’t cause fevers or body aches; plus, they tend to cause coughing only in those who have asthma, says Mayo Clinic allergy specialist Hirihito Kita.

How does he tell one from the other when he feels ill? “If my sneezing turns into a cough after two or three days, then I know it’s a cold. If my sneezing continues without other symptoms for a week, then I know it’s an allergy,” says Kita. He also examines the tissue after blowing his nose. If the mucus turns thick and yellow after a few days of symptoms, it’s likely a cold; mucus that remains thin and clear usually signals an allergy.