Ask an Expert
How can I tell a cold from the flu?
8th September 2015
It’s difficult to tell the common cold from the flu because they have some symptoms in common. Both are viral infections of the respiratory system, caused by a microscopic organism that has entered the body and changed the way some cells work.
The differences to look for between the cold and the flu are in how the symptoms appear, how severe they are and how long they last. The best way to tell the flu from the cold is based on temperature. A symptom of the flu is a sudden fever (38°C or higher).
With a cold, a virus targets the lining of the nose and throat (the upper respiratory tract) and causes these areas to become inflamed. This triggers the production of mucus, resulting in a runny nose and sneezing.
Symptoms can last for about a week but will gradually improve. Younger children and children with a cough can have symptoms that last up to a few weeks.
Common symptoms of a cold include:
- Stuffy or runny nose
- Sore throat (usually one of the first symptoms)
The flu virus infects the entire respiratory system, including the nose, throat, bronchial tubes and sometimes the lungs. The flu occurs most often between December and March. If your child has flu-like symptoms in the summer it could another virus other than the flu.
Flu symptoms come on fast and can make your child feel really out of sorts. Symptoms tend to be at their worst after two or three days. The most common symptoms include:
- Fever that develops quickly (38°C or higher)
- Runny or blocked nose
- Dry, chesty cough
- Muscle aches or joint pain
- Diarrhoea or upset stomach
- Sore throat
The flu can take about a week to shake off, with the fever usually breaking first. The rest of the symptoms may take longer to completely disappear, so your child may still feel tired and achy for up to two weeks or more.
Remember that with both the cold and the flu, your child may not have all the symptoms listed here.