Fever is a temporary rise in body temperature and is a normal reaction to an infection.
Fever helps your body fight infections. Causes of fever include viral infections, such as colds and stomach flu, or bacterial infections, which could be a urinary tract infection or pneumonia.
Normal body temperature can change throughout the day depending on your activity level, but generally normal body temperature taken by mouth (orally) for adults is 37°C (98.6°F) and for children is between 35.5°C and 37.5°C (95.9°F and 99.5°F).1
If you think you or your child has a fever it’s best to rely on a thermometer to determine body temperature. Body temperature can be measured in several places on the body, the most common ones are the mouth, ear, armpit, and rectum.
In children, a rectal temperature of more than 38°C (100.4°F) or armpit temperature higher than 37.5°C (99.5°F) is considered a fever.
For information on the best method and type of thermometer to use for your child, see the article on Caring for Kids website: https://www.caringforkids.cps.ca/handouts/fever_and_temperature_taking.
An adult is considered to have a fever when their body temperature rises above 38°C (orally) or 38.3°C (rectal or ear).
It’s best to see a doctor in the following situations:
Besides a rise in body temperature, you and your child might have other symptoms including:
An increased sweating can lead to a loss of fluids and electrolytes in the body. Also, since you’re not feeling well you may be eating and drinking less than normal, so you are not replacing the fluids and electrolytes that you’ve lost. Both sweating and drinking less than normal can lead to dehydration.
Usually a fever lasts a few days. Along with your doctor’s recommendations, here are a few tips that could make you or your little one more comfortable in the meantime:
Take/give small sips every 15 minutes.
Give your body a chance to recover.
Keep the room around 20 - 21°C.
This allows heat to leave your body.
Remember, fever is a common symptom of most infections, so be on the lookout for other symptoms to help determine if you or your child has a virus or something more serious. Consult your doctor if your child is below 6 months of age or if fever lasts more than 72 hours, or if there are other symptoms and behaviours that concern you.
† Mild to moderate dehydration.
1. MedBroadcast. Fever. Last updated 2019. Available at: https://medbroadcast.com/condition/getcondition/fever. Retrieved: Nov. 25, 2019.