Are Fevers Dangerous?

By Howard J. Bennett, MD

Evaluating children with fever takes up a large portion of a doctor’s day. Although ear infections, strep throat and more serious infections can cause fever, most are the result of simple viral infections. When doctors evaluate children with fever, we are mostly concerned about the cause of the fever, not the fever itself. No one likes it when children are sick. However, it is important for parents to know that except for rare occasions, fever is not dangerous unless it is coming from an outside source.

If a child gets locked in a car, the temperature inside the vehicle can quickly rise to 120 degrees even if it is only 80 degrees outside. If someone exercises vigorously on a hot day with insufficient water intake, the body’s ability to regulate temperature can be affected. In these situations, the mechanisms that keep body temperature in the “safe” range can become overwhelmed. If body temperature goes above 106 degrees, it can lead to heat stroke and death.

The reason it is important to understand how doctors approach fever is because “fever phobia” is so common. Fever phobia is not the same as having a phobia to spiders or flying. However, it implies that someone is very worried that fever itself can harm their child. An influential study published thirty years ago found that 52 percent of parents believed temperatures of 104 degrees or less could result in serious neurological damage.

Whether a person is sick or well, body temperature varies throughout the day. As a result, people are generally cooler in the morning and warmer in the evening. Although sick children can have a high temperature in the daytime, they are more likely to be “burning up” at night.

In the first two months of life, fever is defined as a rectal temperature equal to or greater than 100.4 degrees. If your child is less than two months and has a fever, you should call the doctor right away.

So what should parents do when their children come down with a fever? The first step is to make sure your child does not appear seriously sick. If he does, you should call the doctor immediately. Deciding how “sick” a child looks is more subjective than objective, but the following categories may be helpful:

  • Mildly sick: He is acting fairly normal.
  • Moderately sick: He looks miserable. This implies that he wants to lie around and watch TV or be read to, but isn’t interested in much else.
  • Seriously sick: He is extremely lethargic. This implies that he is very weak, hard to arouse, and does not make eye contact with you. Infants and toddlers who are seriously sick are often inconsolable and very irritable (not normal fussiness).

Febrile seizures are the scariest complication that can occur with fever. (Febrile is the medical word for fever.) A child who was acting normally one minute may suddenly stiffen or jerk his arms or legs and become unconscious the next. His eyes often “roll into his head,” and he may appear blue around the lips. Most seizures only last a few minutes, but it feels much longer to the person watching the episode.

Febrile seizures occur in 3 percent of children between the ages of six months and five years. This means 97 percent will not develop seizures with fever. In the context of this article, the most important thing to know about febrile seizures is that they cannot be prevented with fever-reducing medication. The reason this is important is because parents may blame themselves, a loved one or a babysitter for not preventing the seizure by aggressively treating the fever. This is especially true for the 30 percent of children who have recurrent febrile seizures.

Treating Fever

There is scientific evidence that fever is a normal response of the body’s immune system to fight infection. However, while some doctors recommend not treating fever, most do. The reason for this is because children are more likely to eat, drink and sleep if their body temperature is controlled. Not only does reducing fever make them feel better, but getting sick children to drink helps prevent dehydration. That being said, if your child has a fever and is acting normally, you do not need to give him medication.

It is important to read labels carefully when giving children medicine so you do not make dosing errors. This is especially true if you are tired from having a sick child at home. The following link includes dosage charts that describe the correct way to use acetaminophen and ibuprofen based on a child’s weight or age: Please note that weight trumps age when figuring out the dose for fever medicine. The age option was included because parents may not know their child’s current weight.

In addition to worrying about fever in general, parents are often concerned that fevers are more dangerous if they do not respond to acetaminophen or ibuprofen. This is not true. Neither the height of the fever nor the response to medication is an indication of what is causing the fever.

Some parents alternate ibuprofen with acetaminophen even though there is limited research to support this approach. Two things are important if you treat fever this way. First, keep a chart that records which medicine you gave and at what time. Otherwise you may accidentally give the wrong medicine at the wrong time and overdose your child. Second, remember that ibuprofen is given every six hours and acetaminophen is given every four hours. If you alternate them on this schedule, both medicines will eventually be due at the same time. You can prevent this from happening by putting both medications on a six-hour schedule. That way, your child will get one or the other medicine every three hours. For example, ibuprofen would be due at 9am, acetaminophen at noon, ibuprofen at 3pm, etc.

Another method that parents use to treat fever involves putting a child in a cool bath to bring down the fever. There are two problems with this. First, cool water may lower the child’s skin temperature, but it has little effect on the internal body temperature. Second, putting a feverish child in a cool bath will make him feel like he is freezing. Ironically, the shivering that results may increase his internal temperature.

I don’t recommend bathing a feverish child unless he looks seriously sick to his mom or dad, and we need to determine if the child looks better when the fever comes down. That way I can reassure parents that the fever was making him look sick rather than the illness. The best way to accomplish this is by giving your child a warm bath 30 minutes after a dose of acetaminophen or ibuprofen.


  • It is important to evaluate all fevers, either at home with mild illnesses or in the doctor’s office if indicated.
  • Fevers from illness are not dangerous.
  • Fevers are treated to make children more comfortable and prevent complications like dehydration because they refuse to drink.
  • Avoid the problems that can come from over treating fever.
  • Heat stroke can be prevented with common sense precautions; febrile seizures cannot.

© 2012 Howard J. Bennett. All Rights Reserved.

(This article was originally published on, September 2012.)

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