Fever

What is a fever?

A fever means the body temperature is above normal. You have a fever if your oral temperature is over 99.5°F (37.5°C).

The body's average temperature when it is measured orally is 98.6°F (37°C), but it normally fluctuates during the day. Mild elevation (100.4° to 101.3°F, or 38° to 38.5°C) can be caused by exercise, excessive clothing, a hot bath, or hot weather. Warm food or drink can also raise the oral temperature. If you suspect such an effect on your temperature, take it again in a half hour.

How do I take my temperature?

1. Shake the thermometer until the mercury line is below 98.6°F (37°C).
2. Place the tip of the thermometer under one side of your tongue.
3. Hold it in place with your lips and fingers (not your teeth) and breathe through your nose, keeping your mouth closed.
4. Leave it inside for 3 minutes.
5. After 3 minutes, take the thermometer out of your mouth. Find where the mercury line ends by rotating the thermometer until you can see the mercury and read the temperature.

What causes a fever?

Fever is a symptom, not a disease. It is the body's normal response to infections. Fever helps fight infections by turning on the body's immune system. The usual fevers (100° to 104°F, or 37.8° to 40°C) are not harmful. Most are caused by viral illnesses; some are caused by bacterial illnesses.

How long will it last?

Most fevers with viral illnesses range from 101°F to 104°F (38.3° to 40°C) and last for 2 to 3 days. In general, the height of the fever doesn't relate to the seriousness of the illness. How sick you feel is what counts. Fever causes no permanent harm until it reaches 107°F (41.7°C). Fortunately, the brain's thermostat keeps untreated fevers below this level.

How can I take care of myself?

• Extra fluids and less clothing

  Drink extra fluids. Iced drinks are especially helpful. Body fluids are lost during fevers because of sweating.

  Clothing should be kept to a minimum because most heat is lost through the skin. During the time you feel cold or are shivering (the chills), wrap yourself in a light blanket.

  If the fever is less than 102°F this is the only treatment needed. Fever medicines are not necessary.

• Medicines

  Remember that the fever is helping your body fight the infection. Take medicine only if your fever is over 102°F (39°C) and preferably only if you are also uncomfortable. You should take either acetaminophen or ibuprofen.

  Acetaminophen: Take any one of the acetaminophen products: Tylenol, Anacin-3, Panadol, or Tempra. The dosage is 2 tablets (650 mg) every 4 to 6 hours. 2 hours after they are taken, these drugs will reduce the fever 2° to 3°F (1° to 2° C). Medicines do not bring the temperature down to normal unless the temperature was not very elevated before the medicine was given. Repeated dosages of the drugs will be necessary because the fever will go up and down until the illness runs its course.

  Ibuprofen: Ibuprofen is available in 200-mg tablets without a prescription as Advil, Motrin, etc. The dosage is 2 tablets (400 mg) of ibuprofen every 6 to 8 hours. When you use ibuprofen, stop taking acetaminophen.

  Avoid aspirin: Doctors recommend that children (through age 21 years) not take aspirin if they have any symptoms of a cold or viral infection, such as a fever, cough, or sore throat. Aspirin taken during a viral infection, such as chickenpox or flu, has been linked to a severe illness called Reye's syndrome.

When should I call my health care provider?

Call immediately if:

• Your fever is over 105°F (40.6°C).
• You feel very sick.

Call within 24 hours if:

• Your fever is between 104° and 105°F (40° to 40.6°C).
• Your fever went away for more than 24 hours and then returned.
• You have a fever for more than 3 days.
• You have other concerns or questions.