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Is It a Cold or the Flu?

By Camille Noe Pagán
WebMD Feature

It's no surprise so many people get colds and the flu mixed up. They're both contagious illnesses that affect your lungs and airways, and they have many of the same symptoms. But unlike a cold, the flu can cause serious and even life-threatening problems. That's why it's important to be able to tell them apart.

With the flu, taking antiviral medications in the first 24 to 48 hours can make your symptoms less severe. "Sometimes that can make the difference between sick for a week, or 2 weeks or longer," says Len Horovitz, MD, an internist and pulmonologist at Lenox Hill Hospital in New York City.

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Use these clues to help you decide what you have and what to do about it.

The Flu

The flu is an infection caused by influenza viruses. It usually lasts 1 to 2 weeks and gets better as time goes on.

You probably have the flu if:

You feel miserable all of a sudden. "With the flu, you usually go from feeling fine to feeling like you were hit by a truck, often in less than an hour," Horovitz says.

You have several severe symptoms. Though you may have cold-like issues such as the sniffles and stuffiness, the flu causes worse symptoms, too. Extreme exhaustion, headache, feeling achy, fever and chills, and even skin that's sensitive to the touch are all classic signs of the flu.

Your cough is "dry." Unlike colds, flu-related coughing is usually dry, meaning it doesn't loosen mucus in your airways. Dry coughs can be painful.


A cold is an infection that's caused by one of more than 200 different cold viruses. Colds usually last 7 to 10 days and get better on their own.

Chances are, you have a cold if:

You're sick but can still function. "Unless you have another medical problem, a cold doesn't usually cause the same extreme exhaustion that the flu does," says Aaron Clark, MD, at The Ohio State University Wexner Medical Center.

You have slightly different symptoms every day or two. "Cold viruses can cause some flu-like symptoms, but you usually have just a few at a time, rather than all of them at once," Horovitz says. "Those symptoms also tend to change a little every few days." For example, you may start with a stuffy nose, then get a sore throat, and have sinus or head pain before you feel better.

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