Dear doctor, what’s the difference between a cold and flu?

30 January 2018

Q: There’s a lot of talk about flu. I don’t think I’ve ever had it but I hear it can be quite severe. What’s the difference between a cold and flu?

A: Colds and flu are not the same but they do share some of the same symptoms, however they are caused by different viruses. Flu can be much more serious than a cold.

A cold can give you more nasal symptoms and symptoms relating to the upper respiratory tract which include:

  • blocked or runny nose
  • sore throat
  • headaches
  • cough
  • sneezing
  • pressure in your ears and face
  • loss of taste and smell
  • high temperature or fever
  • muscle aches and pains
  • feeling exhausted and needing to lie down

It normally develops gradually over a day or two and you start feeling better after a few days but can sometimes last up to two weeks. Flu tends to come more quickly and the symptoms appear within one to three days after infection. Fever, fatigue and muscle pain are more likely and more severe with flu.

You may be at a higher risk of complications such as, pneumonia if you:

  • are over the age of 65
  • have serious heart or chest complaints, including asthma
  • have serious kidney disease or liver disease
  • have diabetes
  • have lowered immunity
  • had a stroke or transient ischaemic attack (TIA)

Whether it's a cold or flu, I would advise you to seek medical help if you either:

  • have a chronic condition (such as asthmadiabetes or heart disease)
  • have a very high fever as well as an unusually severe headache or abdominal or chest pain

Dr Zaid Hirmiz is a GP practising at Spire Portsmouth Hospital.


The content of this article is provided for general information only, and should not be treated as a substitute for the professional medical advice of your doctor or other health care professional.

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