Can a cold develop into flu?
Michael W. Smith, MD
Internist, WebMD Medical Expert
Chief Medical Editor, WebMD
The cold and the flu are caused by different viruses. So a cold can’t turn into the flu. But there’s nothing stopping you from getting a cold and the flu at the same time or a few days apart. You catch a cold and the flu in very similar ways - being around someone who is sick, or touching something, like a phone or door knob, that someone touched and contaminated with a virus. The common cold is generally a mild infection that lasts for 4 to 5 days and gets better on its own. Sometimes, you may feel sicker after a few days if the cold leads to a sinus infection or bronchitis.
The flu is worse and hits you like a ton of bricks. One minute you feel fine, and a few hours later it hurts to get out of bed. The flu usually resolves on its own after a week or so, but it can also lead to a sinus infection or bronchitis and, unusually, even pneumonia. Neither the cold not the flu typically has nausea or other stomach problems. If you have those symptoms, there is a good chance you have another type of infection or something else.