Fever is probably the number one reason for parents to call their pediatrician. I'd like to give you my slant on this important subject.
There's a cliché in pediatrics that "fever is a friend", and that's usually true. The elevated temperature mobilizes the immune system to repel invading viruses and bacteria. As a dramatic example, the strain of streptococcus that causes most "strep" throats grows luxuriantly in the lab at 98.6 degrees, but raising the temperature to 104 stops it in its tracks.
Why then do people fear fever so much? The prevailing notion seems to be that high fevers cause brain damage, but that is essentially untrue. In occasion severe cases, of course, a high fever signals a truly dangerous infection such as meningitis, typhoid, malaria, etc. Because most families know of such instances in earlier generations, the belief is that the fever caused the fatal outcome or the permanent damage that those diseases often produced. The truth is that the brain is able to act like a thermostat and keep the temperature from going beyond a safe range; i.e. about 106.5 degrees. The only exceptions are devastating infections of the brain itself, as in bacterial meningitis, most of which are now prevented by immunization.
Do we treat fever? Generally, we do, but more for the child's comfort than because it is urgent to do so. A small percentage (1-2%) of pre-school-aged children have convulsions when the temperature goes up suddenly. These events are terribly upsetting, but produce no lasting damage. I went through two such episodes with one of my children, the last with a 106.4 fever, but I can attest to the happy outcome. Some children with a tendency to have such seizures will be put on preventive medication, but side effects can be troublesome.
The important issue to the doctor is the cause of the fever. The vast majority of childhood fevers are caused by viral infections, which need not be treated with antibiotics. Except in the early weeks of life, fevers are in themselves never a cause for alarm. Most go away by "lysis"; that is, they go up each day, usually in the evening, but less each day. It is common to run a low-grade elevation for weeks when recovering from an infection. A fever that lasts over a week with no apparent cause is known as an "FUO" (fever of unknown origin) and calls for a thorough investigation. A fever that goes higher later in the course of an illness often means secondary bacterial infection and should be checked. It is always wise to assume that a child is contagious in the early stages of a febrile illness. If he or she has 101 degrees or higher one evening, don't send the child to school or day care the next morning.
How to treat fevers? The goal is comfort, not getting the temperature to normal. Ibuprofen (Advil, Motrin) is replacing acetaminophen (Tylenol) because it lasts longer and is anti-inflammatory as well. The dose of each is about a teaspoon per 22 pounds; for infants, 0.8 ml of the drops per 10-12 pounds.
Aspirin was abandoned years ago because of safety concerns. Acetaminophen comes in a suppository (Feverall) for children who are vomiting or won't take oral medicine. Gentle sponging with lukewarm water is helpful for very hot children. Never use alcohol. If the child shivers, the water is too cool and the temperature will rise again. Keep the child dressed as lightly as possible, and encourage liquids by mouth as much as you can.
One last point - call if you are worried. Many serious infections do not produce high fevers because the patient is unable to marshal enough resources to fight them off. A pale, lethargic, vomiting child with a 100 degree temperature is probably much sicker than a screaming baby with a 105!