Fever

Fever

Corrine Langill, RN, BScN

Manager, Health Promotion and Injury Prevention 

Children's Hospital of Eastern Ontario

Fevers often make parents very worried.  But a fever isn't harmful, it's just a sign that a child is fighting an infection, usually a virus.  Fevers are also common after vaccinations.  Don't fret about the number on the thermometer.  The way your child looks, feels and behaves is more important.  When their temperature is high, children will feel unwell and look tired, but should feel better after the fever is treated. 

Parents often have a pretty good idea whether their child has a fever or not, just by touch.   To check, take your child's temperature in the bottom (rectal) or by mouth (under the tongue-oral), with a glass or digital thermometer.   A temperature of 38oC or higher means your child has a fever.  Babies and very young children can't hold a thermometer under the tongue, so will need their temperature taken by rectum.  Ear thermometers or forehead strips are not accurate. 

Children sometimes have seizures when they have a fever (febrile seizures).  Seizures with fever can be scary but do not cause any harm.  Most will only last for a couple of minutes and will stop on their own.  They happen in 1 out of every 20 children with a fever, so are fairly common.

Taking care of your child at home

Children need more fluids when they have a fever, so give extra fluids often.  Dress children lightly, in just one layer of clothing. They don't need to be bundled up in blankets, even if they are shivering. 

Fever medicines

You don't have to treat your child's fever, but fever medicine will reduce the fever and will make your child more comfortable.  Fever medicine does not  prevent febrile seizures.  Remember that fever medicines will not take the fever away completely, and won't stop the fever from coming back.  You'll need to repeat the medicine as needed to make sure your child stays comfortable, and keeps drinking lots of fluids. 

Ibuprofen (Advil®, Motrin®) works better for most children, so try that first.  If your child doesn't feel better in 1 hour, you can try acetaminophen (Tempra®, Tylenol®).  If your child has chicken pox, use acetaminophen.  Never give your child Aspirin® (ASA).

Fever medicines come in different concentrations (the number of mg of medicine in each mL, tablet or suppository.  Check the concentration on the bottle, and read the package directions carefully.  Use your child's weight (not age) to find the right dose.

When to see a doctor

Most children don't need to see a doctor for a fever.  Bring your child to your family doctor if your child:

  • Has a fever for more than 4 days;
  • Is not getting better after 1 week of being sick;
  • Develops an ear ache.

You'll need to come to the emergency department if your child:

  • Is under 3 months and has a fever;
  • Is very irritable or sleepy and doesn't improve with fever medicine;
  • Has trouble breathing;
  • Has signs of dehydration, like: dry mouth, or is not passing urine (peeing) at least every 8 hours;
  • Has a headache or sore neck that does not go away with fever or pain medicine.

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