Fever is one of the most common reasons for parents to bring their children in for a doctor's visit. Parents tend to worry less about a headache, diarrhea, or even a fracture than a high fever. Regardless of cultural background or socioeconomic level, parents worry that their children might suffer brain damage caused by high temperature.

However, virtually all doctors know that an elevated temperature induced by a viral infection never causes injury to the brain. Instead, it is the underlying infection that sometimes damages the brain. As long as the fever is caused by a minor viral infection, it is unnecessary to obsessively worry about the high temperature itself. (However, any fever is potentially dangerous for children under the age of two months. A child of this age who experiences a fever should be taken to the pediatrician.)

What Causes Fever?

Fever is usually a normal response to a state of inflammation in the body. For children, the most common causes of fever are viral infections and minor bacterial infections, with viral infections causing the majority of fevers. This is a good thing, because the vast majority of children get better on their own without suffering long-term disabilities or complications.

Bodies generate a fever to shorten the duration of the infection. At an elevated temperature, the immune system works faster and more effectively. In short, the fever is created by the body and not by the invading viruses or germs. It makes inherent sense, then, that the body would not do something to harm itself. Therefore, under most circumstances fevers are harmless.

What Is Normal Body Temperature?

This sounds like a straightforward question that everyone should be able to answer, but many parents worry themselves sick about a slightly elevated temperature that may not be a fever at all. To understand fever, you must first understand the normal range of human body temperatures.

A lot of people believe any temperature that is higher than 98.6°F is a fever. However, most medical professionals agree that a fever is any properly measured body temperature that is at or higher than 100.4°F. Anything lower than that is not considered a fever at all. Even a fever of 100.4°F or higher is considered a very slight temperature (or low-grade temperature, as doctors call it). A moderate temperature is one that is higher than 102.2°F, and a high temperature is anything more than 104°F.

A healthy child's body temperature fluctuates throughout the day. The body's temperature tends to drop to its lowest in the middle of the night, and it rises to its peak in the late afternoon. In addition, the body's temperature can be affected by a child's emotional state, activity level, and even environmental conditions. Not taking this variation into consideration when interpreting a temperature is a common mistake that many parents make.

More importantly, the exact degree of the child's temperature is less significant than how long the fever lasts and how the child looks. Taking a child's temperature may clue you in as to whether your child has a fever, but it does not give you any clues about what might be causing the fever — nor does it provide any information on the severity of the illness.

How High Is Too High?

One of the questions parents most frequently ask is, “How high does the temperature have to get before I should bring my child to the emergency room?” This question implies that when the temperature is too high, bodily harm will occur. This is, however, generally not true.

Under normal circumstances, a fever generated by the body itself (that is, not by a super-heated external environment) does not raise the child's temperature above 107°F. Experienced pediatricians rarely see children whose fever runs higher than 106°F. (While temperatures this high are uncommon, they are definitely not unheard of.)

Most children who run a fever have a cold or other viral infection, and they generally recover uneventfully. In other words, a high fever does not necessarily mean someone has a bacterial infection. The point is that the degree of the fever does not always correlate with the severity of the underlying illness.

It is true, however, that if a child's temperature rises above 107°F, the body is not likely to tolerate it well for very long. Fortunately, a body temperature above this level does not happen except in extraordinary circumstances, so most of the time, parents do not have to worry about temperature going out of control.

Fever caused by a cold or other viral infection usually does not rise above 102°F. If your child's temperature rises above that point and stays there without fluctuating for a period of time, you should visit your pediatrician.

Hot Headed

Another misconception that many parents have is that you can tell where the infection is located by simply locating the spot on the child's body where the temperature is hottest.

A lot of parents say that they are particularly concerned because the head feels very hot to the touch compared to the rest of the body. They are worried because they think this pattern could indicate that there is an infection in the child's head. Similarly, if the belly feels very hot, they believe the infection must be lodged in the stomach.

Unfortunately, there is no basis for this belief. Otherwise, it would be a lot easier to gauge the source of infections. When a child's head feels hot, it simply means that she could be running a fever. Having a hot head does not mean that the infection is inside the head or is more serious than heat perceived anywhere else on the body.