Infection & Disease

WHEN YOUR CHILD HAS A FEVER

Not a day goes by that I don’t see a patient in my office with a fever. It is one of the most common symptoms seen in Pediatrics, and also one many parents are fearful of. There are many misunderstandings and concerns about the dangers of fever that I hear from parents, and would like to take the time now to clear things up. 

What is a Fever?

Fever means the body temperature is above normal. A true fever is a temperature above 100.4°F. Fever is a symptom not a disease. It is the body’s normal response to illness or infection. Most fevers in children are caused by viral illness such as colds or the flu, and last for 2-3 days, but can last up to 5 days. Some fevers are caused by bacterial illnesses such as strep throat or bladder infections. We worry more about children with fever when it lasts longer than 5 days in a row – this will prompt further investigation by the Pediatrician, possibly through blood work, xrays, and urine tests. Teething does not cause a true fever.

Is fever dangerous for my child?

It is a common misconception that all fevers are dangerous for children, when in fact they are one of the body’s protective mechanisms against infection. Fevers turn on the body’s immune system. Most fevers (100-104°F, or 37.8-40°C) that children get are helpful, not harmful. Only body temperatures over 108°F (42°C) can cause brain damage. Fortunately the brain’s natural thermostat keeps untreated fevers well below this level. The body temperature goes this high only with extreme environmental temperatures (for example, if the child is confined in a closed car in hot weather).

How can I take care of my child?

Extra fluids and light clothing will help prevent overheating. Encourage your child to drink extra fluids and don’t worry as much about solid foods. Popsicles and cold drinks are helpful. Body fluids are lost during fevers because sweating. Clothing should be kept to a minimum because most heat is lost through the skin. Do not bundle up your child; it may cause a higher fever. During the time your child feels cold or a shivering (the chills), give him/her a light blanket. 

Medicines to reduce fever

Remember that fever is helping your child fight the infection. Fever medicines are not always needed. Fevers only need to be treated with medicine if they cause discomfort. That usually means fevers above 102°F (39°C). Try to avoid giving fever reducing medications for lower fevers, as it may disrupt the body’s natural defenses against the infection. Because the brain has a natural thermostat, fevers from infection usually top out at 103°F to 104°F (39.4°C to 40°C). Have your child seen right away if fevers are over 105°F. 

Fever reducing medicines start working in about 30 minutes, and 2 hours after they are given these drugs will reduce the fever 2-3°F. Medications do not bring the temperature down to normal unless the temperature was not very high before it was given. Fever will naturally go up and down until the illness runs its course. If your child is sleeping, don’t awaken him or her for medicines.

Acetaminophen: Children older than 2 months of age can be given acetaminophen (Tylenol). Give the correct dosage for the child’s weight every 4-6 hours. Never give more than 5 doses in any 24 hours.

Ibuprofen: Ibuprofen (Advil, Motrin) is approved for infants over six months of age. Give the correct dosage for your child’s weight every 6-8 hours. However, there is evidence that ibuprofen may further reduce the body’s ability to fight infection because it reduces the inflammatory response, not just the fever.

Avoid aspirin:  Children (through age 21 years) should not take aspirin for fevers.  Aspirin taken during a viral infection, such as chickenpox or flu, has been linked to a severe illness called Reye’s syndrome. If you have teens, warn them to avoid aspirin.

When should I call my child health care provider?

Call IMMEDIATELY if:

  • Your child is less than 3 months old and has a fever.
  • The fever is over 104°F (40°C) and does not improve 2 hours after giving fever medicine.
  • Your child looks or acts very sick.
  • Your child has been in a hot car.
  • The child has any serious symptoms, such as fever along with severe headache, confusion, stiff neck, trouble breathing, rash, or refusing to drink.
  • Your child has a fever and recent travel outside the country to high risk area.

Call within 24 hours if:

  • Your child is 3-6 months old (unless the fever is due to an immunization shot).
  • Your child has had a fever more than 24 hours without an obvious cause or location of infection and your child is less than 2 years old.
  • Your older child has had fever for more than 3 days.
  • The fever went away for over 24 hours and then returned.
  • You have other concerns or questions.

Fever Myths and Facts

Misconceptions about the dangers of fever are common. Fears about harmful side effects from fever cause lost sleep and unnecessary stress for many parents.

MYTH: Anyone can have a febrile seizure (seizure triggered by fever).

FACT: Only 4% of children have febrile seizures. They are scary to watch, but they usually stop within 5 minutes and cause no permanent harm. Children who have had febrile seizures do not have greater risk for developmental delays, learning disabilities, or seizures without fever.


MYTH: If the fever does not come down (if you can’t “break the fever”), the cause is serious.

FACT: Fevers that don’t respond a fever medicine can be caused by viruses or bacteria. Whether the medicine works or not doesn’t relate to the seriousness of infection. How sick your child looks is what is important.


MYTH: Once the fever comes down with medicines, it should stay down.

FACT: The fever will normally last for 2-3 days with most viral infections. The fever will go away and not return once your child’s body overpowers the virus (usually by the fourth day).


MYTH: Feed a cold, starve a fever

FACT: This old saying should be ignored. Fevers cause the body to lose fluids through sweating and breathing. Children with fevers need extra fluids. Children with fever may or may not be hungry for food but if they are hungry, allow them to eat as they choose.


Remember that fever is helping to fighting off your child’s infection


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2 Comments

  • Lisa Domezio

    Love love love this post! A fever is something I worry about normally and now I have this resource. Question. My son’s temperature is normally 97.5-97.7. Does his temp still need to be at 100.4 to be considered a fever? I run low as well and have always wondered.

    • Dr Jackson

      Hi Lisa! I am glad this post is helpful for you and thanks for your question. Actually, yes, you would still consider 100.4F a fever even if he typically runs a little lower than “normal” temperatures. 100.4F or 37C is just a standard scientific measurement for fever. Hope that helps!

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