Fever refers to an elevation in body temperature. Technically, any body temperature above the normal oral measurement of 98.6 F (37 C) or the normal rectal temperature of 99 F (37.2 C) is considered to be elevated. However, these are averages, and your normal temperature may actually be 1 F (0.6 C) or more above or below the average of 98.6 F. Body temperature can also vary up to 1 F (0.6 C) throughout the day.

Thus, fever is not considered medically significant until body temperature is above 100.4 F (38 C). Fever serves as one of the body's natural defenses against bacteria and viruses which cannot live at a higher temperature. For that reason, low fevers should normally go untreated, unless accompanied by troubling symptoms.

Viral fever

Illnesses caused by viruses are among the most frequent causes of fever in adults. Symptoms can include a runny nose, sore throat, cough, hoarseness, and muscle aches. Viruses also may cause diarrhea, vomiting, or an upset stomach.

Bacterial fever

Central nervous system (brain and spinal cord) infections can cause fever, headache, neck stiffness, or confusion. A person may feel lethargic and irritable, and light may irritate the eyes. This could represent meningitis or a brain infection, so the person should go immediately to the doctor.

Lower respiratory system infections include pneumonia and bronchitis can cause fever. Symptoms include coughing, difficulty breathing, thick mucus production, and sometimes chest pain.

Upper respiratory system infections occur in the throat, ears, nose, and sinuses. A runny nose, headache, or sore throat accompanied by a fever may indicate a bacterial infection.

Infection of the genitourinary system may cause a person to have a burning sensation when urinating, blood in the urine, the urge to urinate frequently, and back pain along with a fever. This would indicate an infection in the bladder, kidney, or urinary tract. Antibiotics would treat such an infection.

The following medications may be used at home to treat a fever:

-- Acetaminophen can be used to lower a fever. The recommended pediatric dose can be suggested by the child's health-care provider. Adults without liver disease or other health problems can take 1000 mg (two "extra strength" tablets) every four to six hours or as directed by your physician.

--Ibuprofen (Motrin/Advil) can also be used for fever in patients over 6 months of age. Discuss the best dose with your doctor. For adults, 400-600 mg (two to three 200 mg tablets) can be used every six hours.

--Aspirin should not be used for fever in children or adolescents. Aspirin use in children and adolescents during a viral illness (especially chickenpox and influenza) has been associated with Reye syndrome. Reye syndrome is a dangerous illness which causes prolonged vomiting, confusion, and even coma and liver failure.

An individual with a fever should be kept comfortable and not overdressed. Overdressing can cause the temperature to rise further. Tepid water (85 F [30 C]) baths may help bring down a fever. Never immerse someone in ice water. This is a common misconception. Never sponge a child or an adult with alcohol; the alcohol fumes may be inhaled, causing many problems.

The best way to prevent fevers is to reduce your exposure to infectious diseases. One of the most effective ways to do that is also one of the simplest — frequent hand washing.

Teach your children to wash their hands often, especially before they eat and after using the toilet, after spending time in a crowd or around someone who's sick, and after petting animals. Show them how to wash their hands vigorously, covering both the front and back of each hand with soap, and rinsing thoroughly under running water. Carry moist towelettes or hand sanitizer with you for times when you don't have access to soap and water. When possible, teach your kids not to touch their noses, mouths or eyes — the main way viral infections are transmitted.

In addition, turn away from others and cover mouths when coughing and noses when sneezing.