Cold or flu: when to seek medical help?

Cold or flu: when to seek medical help?

Cold or flu?

The cold and flu are respiratory infections caused by viruses that attack the nose, throat and lungs.

The common cold is caused by a virus: 6 different types can result in more than 200 versions of the virus. A majority of colds (from 30 to 40%) are caused by rhinoviruses, viruses that adapt well inside nasal passages and are able to grow there.

Three types of viruses cause the flu: A (the most dangerous for humans), B and C.

The virus infects tissues that line the inside of the mouth, throat and nose. Tissues become inflamed, which causes sneezing, sore throat, runny nose and nasal congestion. The cold is rarely accompanied by a fever, aches or weakness.

The flu is characterized by a sudden fever that lasts 3 to 4 days, general weakness, muscle aches, headaches and lung problems.

The cold lasts on average 7 days.

People who contract the flu generally start feeling better in 1 to2 weeks.

In Canada, colds typically appear after the start of school, in the middle of winter and in early spring. Children catch about 5 to 7 colds a year, while adults have from 2 to 3.

About 10 to 40% of the Canadian population will get the flu starting in the fall (October, November) and lasting until spring (March, April).

Bacterial sinus or lung infections are the main complications of the cold or flu. Some people will develop an ear infection.

Symptoms Flu Cold
Fever
  • Common
  • Temperature between 38 °C and 40 °C (between 100.4 °F and 104 °F)
  • Sudden onset
  • Absent or mild
Cough
  • Common
  • Sudden onset
  • Common
  • Mild or moderate
Headache
  • Common
  • Sometimes intense
  • Rare
Aches and pains
  • Common
  • Sometimes intense
  • Rare
  • Mild
Fatigue
  • Common
  • Intense
  • Duration: a few days, sometimes longer
  • Common
  • Mild
Nausea and vomiting
  • Common in children
  • Rare in adults
  • Often accompanied by diarrhea and abdominal pain in children
  • Rare
  • Mild
Runny nose or nasal congestion
  • Rare, more common in children
  • Common
Sneezing
  • Rare
  • Common
Sore throat
  • Common
  • Common