Fever: First aid

Fever is one of your body's reactions to infection. Usually the normal body temperature doesn't exceed 99 F (37.2 C). The value of 98.6 F (37 C) listed as normal body temperature is only a general guide. Isolated temperature elevations usually aren't dangerous in an adult until the temperature reaches 103 F (39.4 C). Taking aspirin or acetaminophen (Tylenol, others) usually reduces a fever in adults. Don't give aspirin to children younger than 17 years of age. The use of aspirin has been linked with Reye's syndrome — a rare but serious illness that can affect the blood, liver and brain of children and teenagers after a viral infection.

How to take a temperature

You can choose from several types of thermometers. Today, most have digital readouts. Some take the temperature quickly from the ear canal and can be especially useful for young children and older adults. Others can be used rectally, orally or under the arm. If you use a digital thermometer, be sure to read the instructions, so you know what the beeps mean and when to read the thermometer. Under normal circumstances, temperatures tend to be highest around 4 p.m. and lowest around 4 a.m.

Due to the potential for mercury exposure or ingestion, glass mercury thermometers are being phased out.

Rectally (for infants)

To take your child's temperature rectally:

-Place a dab of petroleum jelly or other lubricant on the bulb.

-Lay your child on his or her stomach.

-Carefully insert the bulb one-half inch to one inch into the rectum.

-Hold the bulb and child still for three minutes. To avoid injury, don't let go of the thermometer while it's inside your baby.

-Remove and read the temperature as recommended by the manufacturer.

A rectal temperature reading is generally 1 degree F higher than an oral reading.

Orally

To take your temperature orally:

-Place the bulb under your tongue.

-Close your mouth for the recommended amount of time, usually three minutes.

-If you're using a nondigital thermometer, rotate it slowly after removing it from your mouth until you can read the temperature.

Under the arm (axillary)

You can also use an oral thermometer for an armpit reading:

-Place the thermometer under your arm with your arms down.

-Hold your arms across your chest.

-Wait five minutes or as recommended by your thermometer's manufacturer then remove and read the temperature.

-An axillary reading is generally 1 degree F less than an oral reading

Get medical help for a fever in these cases:

-A baby younger than 3 months has a rectal temperature of 100.5 F (38 C) or higher or an ear temperature of 99.5 F (37.5) or higher

-If a child older than 3 months maintains a temperature of 103 F (39.4 C) after a few hours of home treatment

-If an adult has a temperature of greater than 104 F (40.0 C) or a temperature of 101 F (38.3 C) that persists for longer than 3 days

Call your doctor immediately if the fever is accompanied by severe headache, stiff neck, swelling of the throat or mental confusion, or if you see unusual rashes or bite marks.