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Fever in children

Fever is the human body’s normal response when exposed to certain viruses or bacteria. It is characterized by an increase in body temperature. It is the body’s normal defence mechanism.

Recognizing fever in children

Fever is very often accompanied by other symptoms, such as:

  • chills;
  • skin that is hot to the touch;
  • feeling cold;
  • rapid heartbeat;
  • headache;
  • rapid breathing;
  • mottled skin.

If your child presents one of these symptoms and you notice a reduction in activities, you should check your child’s temperature.

Your child has a fever if his or her temperature is equal to or higher than:

  • 38.5 °C (101.5 °F) when the temperature is taken rectally;
  • 38.0 °C (100.4 °F) when the temperature is taken orally (under the tongue);
  • 37.5 °C (99.0 °F) when the temperature is taken in the armpit;
  • 38.0 °C (100.4 °F) when the temperature is taken in the ear.

For children aged 4 to 18 months, fever can be associated with teething. See the From Tiny Tot to Toddler This hyperlink will open in a new window. guide for more information.

For children under the age of 18, in particular those aged 3 months to 5 years, when a fever increases very quickly, it can cause involuntary movements of all (or some) of the limbs, a loss of consciousness or a momentary blackout. These movements are called febrile seizures. They usually do not cause serious harm to the child and do not damage the brain. The seizure does not usually last long but can last up to 15 minutes.

The causes of febrile seizures are still unknown. The risk of having them is higher if family members (parents, brothers, sisters, etc.) have had febrile seizures.

Taking a child’s temperature

There are several types of thermometers that offer different methods of taking temperature.

The best method depends on the child’s age:

  • From birth to 2 years old: take the temperature rectally.
    If the child is too agitated, you can take his or her temperature in the ear, but it will be less accurate.
  • From 2 to 5 years old: take the temperature rectally.
    If the child is too agitated, you can take his or her temperature in the mouth, ear or armpit, but it will be less accurate.
  • Over 5 years old: take the temperature orally or rectally.
    If the child is too agitated, you can take his or her temperature in the ear or armpit, but it will be less accurate.

Mercury thermometers are not recommended because they can be dangerous if they break.

The temperature taken in the ear or armpit is less accurate. Use these methods as a last resort.

What to do if a child has a fever

You can help your child feel better by taking a few simple actions while monitoring the fever’s progression.

Give drinks frequently

When your child has a fever, its body naturally loses a lot of fluid, especially through sweating. It is therefore important he or she drinks plenty of fluids frequently.

  • Give fluids, such as water, milk, juice or broth.
  • Avoid caffeinated drinks such as coffee and tea and highly sweetened and energy drinks. These drinks make you urinate, increasing fluid loss.

When a child has a fever, it’s important to watch for the signs of dehydration.

If your child presents signs of dehydration, you can give him or her rehydration solutions sold in pharmacies, such as Pedialyte®. Don’t hesitate to seek advice from a pharmacist or to call Info-Santé 811.

Other warning signs

If your child has a fever, watch for the following signs:

  • The fever can last from 24 to 72 hours. See the section When to consult a doctor for more information.
  • Your child might be moody and cry more frequently. Be attentive to your child’s wellbeing.
  • If the fever goes down with fever medication, watch for the appearance of other symptoms.

To help your child feel better

To help your child feel better, you can:

  • Help your child to rest;
  • Dress your child in light clothing;
  • Keep your child in a well-ventilated room with the temperature near 20 °C;
  • Regularly offer your child something to drink.

If your child suffers from health problems, consult your pharmacist or Info-Santé 811 before giving him or her over-the-counter medications.

If your child is over 3 months, you can:

  • Give him or her medication containing acetaminophen (ex., Tylenol, Tempra). Respect the quantity and interval between doses recommended on the product label.
  • Generally, the temperature goes down an hour and a half to 2 hours after taking acetaminophen, and then it can go up again. That is how the medication usually works. Nevertheless, you must wait a minimum of 4 hours between doses.
  • If the child vomits, buy acetaminophen suppositories that you insert into the rectum. You must also follow the instructions on the box;
  • Check with your pharmacist if you want to buy over-the-counter cough and cold medication. Your pharmacist can help you find the right medication based on your child’s age and condition.

Things to avoid

When a child has a fever, certain actions should be avoided:

  • Avoid forcing your child to eat; it’s normal for your child to feel less hungry;
  • Avoid baths, alcohol rubdowns and fans because these treatments could cause chills and increase the child’s temperature;
  • Avoid giving Aspirin to children under the age of 18.

When to consult a doctor

If you don’t know if your child needs to consult a doctor, call Info-Santé 811, option 1. A nurse will assess your situation and may be able to give you specific advice The nurse will also be able to tell you if you should consult a doctor quickly.

You can also follow the instructions below to find out whether a call to Info-Santé 811, consultation with a doctor or an emergency consultation are necessary.

Calling Info-Santé 811

Contact Info-Santé 811, option 1 for an assessment by a nurse if:

  • your child is between 3 and 6 months old and has:
    • a fever of 38.0 °C (100.4 °F) or higher for more than 48 hours after receiving a vaccination,
    • a temperature that is too low (36.0 °C or less, taken rectally).
  • your child is under 2 years old and has:
    • a fever of 38.5 °C (101.3 °F) or higher that persists more than 48 hours;
    • a fever that is accompanied by other symptoms (ex., inconsolable crying, irritability, difficulty breathing, rash, febrile seizures, etc.).
  • your child, regardless of age:
    • drinks and urinates less than usual;
    • presents mild to moderate signs of dehydration;
    • presents a fever that increases or appears after dissipating for more than 24 hours;
    • presents symptoms that worsen or do not improve after 7 days;
    • has a febrile seizure but has had one before.

Consultation with a doctor

If the fever increases or persists more than 48 hours or if symptoms other than fever worsen or don’t improve after 48 hours for children under 2 years old or 72 hours for children over 2 years old, you must consult a doctor.

To get a medical appointment, see the page Getting a medical consultation with a health professional.

Go to the emergency department immediately

Go to the emergency department if:

  • your child aged under three months old has a fever of 38.0 °C (100.4 °F) or higher and has not been vaccinated in the last 48 hours;
  • your child, regardless of age, has:
    • a temperature that is too low (36.0 °C or less, taken rectally),
    • a fever of 38.5 °C (101.3 °F) or higher that persists more than 48 hours AND is not alleviated by fever medication;
  • your child has a chronic illness or a weakened or deficient immune system AND has a temperature over 38.5 °C or 101.3 °F;
  • your child presents moderate to severe signs of dehydration;
  • its complexion is pale or its skin colour seems abnormal;
  • its breathing is faster or difficult;
  • he or she does not respond to stimulation, he or she seems amorphous and less alert;
  • your child has had febrile seizures for the first time. In this case, you must consult within 4 hours.

Last update: December 15, 2023


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