Fast Facts about Fevers

Fast Facts about Fevers

Most bacteria and viruses that cause infections in humans thrive best at 98.6 degrees F (37C). Raising the temperature a few degrees can give the body the winning edge. In addition, a fever activates the body’s immune system, accelerating the production of white blood cells, antibodies, and many other infection-fighting agents.

Brain damage from a fever will not occur unless the fever is over 107.6 degrees F (42C) for an extended period of time.

Untreated fevers caused by infection will seldom go over 105 degrees unless the child is overdressed or trapped in a hot place. In a neurologically normal child, the brain’s thermostat will stop the fever from climbing above 106 degrees F.

About 4% of children will sometimes have seizures with fever. These febrile seizures are caused by rapid increase in temperature, not by the height of the temperature. Once a child already has a high fever and a febrile seizure, a febrile seizure is unlikely to reoccur with the current illness. In any event, typical febrile seizures are over in moments with no lasting consequences.

While 98.6 degrees F is considered the normal core body temperature, this value varies between individuals and throughout the day. The daily variation is minimal in children less than six months of age, about 1 degree in children 6 months to 2 years old, and gradually increases to 2 degrees per day by age six. A person’s baseline temperature is usually highest in the evening. Body temperature, especially in children, is normally raised by physical activity, strong emotion, eating, heavy clothing, elevated room temperature, and elevated humidity. Rectal temperatures below 100.4 degrees F (38C) may be entirely normal (no fever). A rectal temperature of 100.4 or above should be considered a fever. Lower values might be a fever, depending on the child.

A fever does not necessarily need to be treated. If a child is playful and comfortable, drinking plenty of fluids, and able to sleep, fever treatment is not likely to be helpful.

Steps should be taken to lower a fever if the child is uncomfortable, vomiting, dehydrated, or having difficulty sleeping. The goal is to bring the temperature between about 100 and 102 degrees F — not to eliminate the fever.

When trying to reduce a fever, first remove excess clothing or blankets. The environment should be comfortably cool (one layer of light weight clothing, and one lightweight blanket to sleep).

Two medicines are useful for reducing fever in children: acetaminophen (Tylenol) and ibuprofen (Children’s Advil or Motrin). Acetaminophen is given every 4-6 hours, and works by turning down the brain’s thermostat. Don’t use under three months of age without first having the child examined by a physician. Ibuprofen is given every 6-8 hours, and helps fight the inflammation at the source of the fever. It is not approved for children under 6 months. Both medicines may be given for stubborn fevers, but be very careful about using the correct dose of each.

A lukewarm bath or sponge bath may help cool a febrile child (after medication is given — otherwise the temperature bounces right back up). Cold baths or alcohol rubs cool the skin, but often make the situation worse by causing shivering, which raises the core body temperature.

Fever is a signal that something is going on in your child. Usually this is a minor illness, but it can be a serious infection, such as meningitis. Any child less than 90 days old with a fever should be examined by a physician right away, to rule out a serious infection (unless there was a DPT shot in the previous 24 hours). Children of any age who have a fever 104 degrees or more should also be seen, unless the fever comes down readily with treatment and the child is comfortable. Any child who has a fever and is very irritable, ill appearing, confused, has difficulty breathing, has a stiff neck, won’t move an arm or leg, or who has a seizure should also be seen right away.

Even without the above symptoms, children under 6 months of age with a fever should be examined by a physician within 24 hours (again unless they just had a DPT), since they may have some infection that needs to be treated. Older children with a fever (6 to 24 months old) who are acting well and have no other symptoms should be seen if the fever lasts >48 hours (or >72 hours if they do have minor cold or flu symptoms).

Dr. Alan Greene

Dr. Greene is the founder of DrGreene.com (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.

  1. nasira

    Hi sir
    I am from India .my daughter is 9n half years old .she is suffering from fever from last 23 days. We check blood urin everything blood normal slightly urine infection is there
    Sir plus tell me Wat to do

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  2. sumaira

    Add your message here some months ago i have a problam plz ans me must ..i hv headch nd hv high fever i faint for few hour like 6 to 7..its repetd every day with me what is this

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    • You need to see a doctor who can do a thorough examination and run tests. “Fainting for a few hours” is not normal. Do you have a way to see a doctor?

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  3. Aimee Orr

    My 7 year old daughter has been having repeated fevers since January. This is her eighth time and seventeenth day of missed school since. They last about 2.5 days and then she’s totally normal. I’ve her to have her blood drawn and urine tested twice. Everything comes out fine. They keep telling me to just give her Tylenol/IB and not to worry. She always complains of being dizzy, headache and soar throat. No puffiness or any other infection symptoms.

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    • BB

      My 7 year old daughter is dealing with this too. They diagnosed her with PFAPA and are wanting to treat each episode with Prednisone. Additionally, we talked to a Natural Doctor who is doing more intensive Lyme Disease testing. You may want to look into both of these. If you do the Lyme test, make sure it is the Western Blot. We’re also looking for ways to treat the cause with dietary changes…cutting out wheat, dairy, processed sugar. Good luck!

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  4. Nick

    Hello my name is nick I’m 13 I had a fever of 106.6 I did not puck I felt really dizzy and lost track of time I called my dad while he was at work he said poor you self some lemmond aid and turn on a fan and put a cold wash cloth on my head and sit with the fan on and with the wash cloth on your head and make sure u keep moving keep awake because I felt I was going to pass out he got home and said don’t go in your room till its coold down do u think he could of done a better job because right now I have a fever of 102.8

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  5. Antwi Prince Eric

    God bless you for this rich information and tips on fever.

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  6. Av.Suresh Wale

    My baby of 20 month suffering fever which is around about 102 faranhit and is rises and fall about four hours twice a day since 15 days.his hemoglobin level is 7 which is low.his input also poor.please advice to improve health of baby.thanks

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  7. Av.Suresh Wale

    My baby of 20 sufferrd from fever since 15 days around 102 degree faranhit. His hemoglobin level is 7 is below normal level his input also decreases considerably. Please advice to impove the health.

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  8. Brian

    The article is titled facts about fevers. But the entire article only references fevers in children. I think you need to retitle the article.

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      • Jeff what

        The article’s title is really misleading !

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        • I’d love to have your input:

          1. What is misleading?
          2. What would a better title be?
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        • R

          I might note that the article is on a site called “Dr. Greene: Let’s talk KIDS health”.

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    • nichole

      i totally agree the article is titled facts about fevers but it only references fevers in children my friend is a 31 year old male who yesterday had a fever of 105.2 and today has a fever of 106 and i was trying to find out information to help him and i thought this article could help but i was wrong

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  9. michelle carvajal

    my son is just about 4months old and I had him seen today and at that time his temp was 101.3 and now its 102.3. What should I do they told me not to bring him back in unless its over 105

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  10. jean keough

    Hi my daughter is 15yrs old day 2 fever runs 102.3 to 104.6. She had this same thing go on three weeks. Back but she fainted had to call 911 they said dehydration fever combo caused her to faint gave her i.v. fluids sent us on our way now here we r 3 weeks later same thing going on any recommendations. Or ideas why this is happening

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