Fever

What is a fever?

A fever is usually a sign of infection or illness. The temperature that indicates a fever depends on how you take the temperature:

Method of Taking Temperature	Fever
Rectal temperature	Over 100.4 F (38.0 C)
Mouth (Oral) temperature	Over 99.5 F (37.5 C)
Armpit (Axillary) temperature	Over 99.0 F (37.2 C)
Ear (Tympanic) temperature	Over 100.4 F (38.0 C) if thermometer is set in rectal mode OR over 99.5 F (37.5 C) if thermometer is set in oral mode

Oral and rectal temperatures are most accurate. Rectal temperatures should be used for children younger than 4 years old and oral temperature for children older than 4 years old.

When should I call a doctor if my child has a fever?

Call a doctor right away:

• If your child is less than 3 months old and has a fever
• If your child has a fever of 105 F (40.6 C) or higher
• If your child appears very sick, even if the fever is not very high

You do not need to call right away, but should see your doctor the following day:

• If you child has fever for more than 5 days
• If your child complains of ear pain, to make sure that your child does not have an ear infection • If your child complains of sore throat, to make sure that your child does not have a strep infection
• If you child complains of burning with urination, to make sure that your child does not have a urinary infection
• If your child has fever, but no symptoms of a cold (cough/runny nose) or stomach flu (vomiting/diarrhea) to explain it

What causes fever?

Fever is the body’s response to fighting infection. Raising the body temperature turns on the immune system and actually helps to fight off bacteria and viruses.

Why do we treat fevers?

The main reason to treat fevers is that they make children uncomfortable. Children are frequently more irritable, cranky, and tired when they have a fever. Often simply treating the fever will make them happier and more interested in their usual activities like playing and eating.

How do I treat a fever?

Simple treatments such as extra fluids and less clothing should be used for all children. Your child burns off extra fluid when he has a fever so he needs more fluids than usual. Do not bundle your child as this may make the fever go higher. A light blanket is OK if your child is shivering or feels cold.

Medicines can be given to reduce fever if your child is uncomfortable and the fever is over 102 F. Tylenol (acetaminophen) can be given to children over 2 months of age, and Motrin or Advil (ibuprofen) can be given to children over 6 months of age. See the Dosages of Common Medications (place link here) portion of this web site for appropriate dosing for your child’s weight and age. Be sure to check over-the-counter cough and cold medicines you are giving your child to make sure that they do not also have acetaminophen or ibuprofen in them. You can easily overdose your child if you do not check the label.

Do not give aspirin or aspirin containing products to a child with a fever. Aspirin has been linked to Reye’s Syndrome a serious illness which causes liver failure and brain damage.

Sponge baths can be used if your child’s fever is greater than 104 F and he is uncomfortable. Use luke warm water as cold water will be too chilling. Always give Tylenol or Motrin/Advil a half hour before the sponge bath to prevent chills. If your child does develop chills, stop the bath and have him dry off. Never add rubbing alcohol to the water when giving a sponge bath.

How long does it take for Tylenol or Motrin/Advil to work?

It may take up to two hours before the fever-reducing medicine starts to work. If your child’s temperature is still high after one hour, wait and check the temperature again after another hour. If the temperature is still high after two hours, it will be too soon to give the medicine you gave earlier. If you gave Tylenol earlier, you could now give Motrin/Advil and if you gave Motrin/Advil earlier, you could now given Tylenol

Is it a bad sign if my child’s fever goes back up several hours after I give a fever-reducing medicine?

No, it is expected that your child’s fever will continue to return as the medicine wears off until the illness runs its course. Your child’s fever will likely go down 2-3 degree F within two hours after you give the medication, but the fever will likely return over the next 4 to 6 hours as the medicine wears off. Tylenol can be given every 4 hours and Advil/Motrin can be given every 6 hours if needed.

Can fevers cause brain damage?

The typical fever cannot cause brain damage. A fever must be higher than 106 or 107 F to cause brain damage.

Some children may have seizures with fever. These seizures do not cause brain damage. Usually febrile seizures run in families. One or both parents may have had febrile seizures as children. Children outgrow febrile seizure with age, usually by age 5 or 6. Up to 1/3 of children who have had a single febrile seizure, will have another febrile seizure. Very few (2 out of 100) will go on to have epilepsy.

What can I do to prevent a seizure in my child if she has had febrile seizures in the past?

Some doctors recommend treating with alternating Tylenol (acetaminophen) and Motrin/Advil (ibuprofen) given 3 hours apart at the first sign of a fever. Unfortunately many children with febrile seizures have a seizure even before their parents are aware that they are developing a fever. Don’t blame yourself if your child has a seizure. Place your child on his side so that he cannot choke on his tongue or saliva. Most seizures will stop in 2-3 minutes on their own. If the seizure does not stop or your child turns blue, call 911 immediately.