Fever Facts

Fevers- Fact or Fiction?

This year, almost everyone has had their temperature taken significantly more than ever have before! Taking your temperature is a good way to determine if you have a fever. Almost all fevers are caused by a new infection, but not all fevers require treatment or indicate a serious problem. Most fevers with viral illnesses range between 101° and 104° F, last 2 or 3 days, and are not harmful. These are the cutoffs for fevers using different types of thermometers:

  • Rectal, ear, or forehead temperature: 100.4° F or higher
  • Oral mouth temperature: 100° F  or higher
  • Under the arm Armpit temperature: 99° F  or higher

Colds, flu, and other viral infections are the most common cause. Fever may be the only symptom for the first 24 hours. Roseola may cause a fever for 2 or 3 days and then a rash appears. Common causes of bacterial infections that may cause a fever are bladder infections- the most common cause of silent fever in girls, strep throat, and sinus infections. Sinus infections are a complication of a cold, and may cause a fever to come back.

Children may get a fever after vaccines, which usually begins within 12 hours and lasts 2 to 3 days. This is normal and harmless. It means the vaccine is working. If a newborn gets a fever within the first 3 months of life, it can be very serious. Prompt treatment is essential to determine the cause and give any treatment necessary. Meningitis is also a very serious bacterial infection of the membrane that covers the spinal cord and brain. The main symptoms are a stiff neck, headache, and confusion. Younger children are lethargic or so irritable that they can’t be consoled. If not treated early, this can cause brain damage.

There are a lot of myths about fevers, so we wanted to help you separate the facts from fiction!

  1. Can being overheated cause a fever? Yes! The fever is usually low grade and goes away within a few hours of moving to a cooler place, resting, and drinking extra fluids.
  2. Can teething cause a fever? No, teething does not cause fevers!
  3. Are all fevers bad for children? No, fevers turn on the body’s immune system and help the body fight infection. Normal fevers between 100° and 104° F are good for sick children.
  4. Do fevers above 104 cause brain damage? Fevers with infections don’t cause brain damage. Fevers over 106° F are considered very high and it is important to bring it down. Only temperatures above 108° F can cause brain damage. It’s very rare for the body temperature to climb this high. It only happens if the air temperature is very high. An example is a child left in a closed car during hot weather.
  5. Can a fever trigger a seizure in all children? Only 4% of children can have a seizure with fever. These seizures are scary to watch, but they usually stop within 5 minutes and don’t cause any permanent harm. They don’t increase the risk for speech delays, learning problems, or seizures without fever.
  6.  Should all fevers be treated with medicine? Fevers only need to be treated if they cause discomfort. Most fevers don’t cause discomfort until they go above 102° or 103° F.


Treatment for all fevers include more fluids and less clothing! Good hydration replaces sweat. It also improves heat loss from the skin. Fever reducing medication such as ibuprofen or acetaminophen can be used if the fever is causing discomfort. Never use aspirin on children, aspirin can cause Reye Syndrome which is a rare but serious brain disease. Sponging is an option for high fevers but not required. Always try fever medicine first, and only use sponging if the fever is above 104°. Use lukewarm water 85 – 90° F and sponge for 20-30 minutes. If your child shivers or becomes cold, stop sponging or make the water warmer.


  • Fever goes above 104° F
  • Any fever occurs if less than 12 weeks old
  • Fever without a cause lasts more than 24 hours if age less than 2 years
  • Fever lasts more than 3 days 72 hours
  • Seek immediate treatment if your child is having trouble breathing, won’t stop crying or cries when touched or moved, or seems weak and  unable to stand or move normally.

If you are concerned about your child’s fever or have other questions about your child’s health, contact The Pediatric Center for an appointment. With night and weekend hours available, The Pediatric Center is here for you when you need us! We have been serving eastern Idaho for over 55 years providing quality pediatric care from birth to the age of 19.


Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.