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Public Health - Seattle & King County

Cold versus Flu?

Colds and flu look alike

The common cold and the flu are different illnesses caused by different viruses, but they share similar symptoms. Both can cause cough, sore throat, sneezing, fever, runny or stuffy nose, body aches, chills, tiredness, diarrhea, and vomiting. In fact, it can be difficult even for doctors to tell the difference between them based on symptoms alone.

Which symptoms you get and how ill you feel will vary depending on many things, including your general health, how long you've been sick, and whether you also have a bacterial infection (such as sinusitis, ear infection, or pneumonia).

Some general differences to look for:

Common Cold Flu (including seasonal and H1N1 influenza)
Usually milder illness Usually illness is worse than common cold
Often develops over a few days Often develops suddenly and quickly grows worse
These symptoms are less common and more mild: fever, body aches, extreme tiredness, dry cough These symptoms are more common and intense: fever, body aches, extreme tiredness, dry cough
More likely to have runny or stuffy nose Less likely to have runny or stuffy nose
Generally does not result in serious health problems Can result in serious health problems, such as pneumonia, bacterial infections, or hospitalization

However, not every case of the common cold or the flu will fit the above descriptions. Some people can get mild cases of flu, and some will have more severe colds.

When to contact your doctor

If you have concerns about whether you have the flu -- especially if you have a chronic health condition -- talk to your doctor or health care provider. Antiviral medicines can help prevent serious health problems from the flu, but they work best if you take them within 48 hours of the first flu symptoms. Call your health care provider if:

  • You have a chronic health condition and have fever plus either cough or sore throat, or
  • Your symptoms are more severe than usual, or
  • Your symptoms are lasting longer than usual, particularly if you were getting better then started getting worse