A: Fever is one of the most common reasons parents call or visit their child's doctor. But fevers in and of themselves are far less harmful than most parents believe; in fact, the height of a fever seldom causes any specific damage to a child. Most often, a fever simply indicates that your child's body is trying to fight off an infection. Although a fever can alert you that your baby is sick, any other symptoms your child displays provide more important clues to the cause of her illness.
Although parents who insist their baby has a fever because she is "warm to the touch" are usually correct, you should always take your baby's temperature if she feels warm. Body temperature can be measured in a number of locations (in the mouth, rectum, or ear, and under the arm) with a variety of devices (old-fashioned mercury thermometers, electronic thermometers, and infrared ear thermometers). Parents should ask at their baby's first checkup which method the doctor recommends, and then have him demonstrate how to take a temperature and understand the results. Rectal temperatures are generally the most accurate; oral readings are about 1 degree lower, while temperatures taken in the armpit are about 1 degree lower than oral.
If your child is under 3 months of age and has a rectal temperature greater than 100.4°F, take her to the doctor right away -- the immune system of a baby this age is still immature, making her more susceptible to serious infections like meningitis. (For this reason, feverish newborns up to 6 weeks old may need to stay in the hospital for observation and treatment.) For a 3- to 6-month-old, a temperature of 101°F or higher should prompt a call to the doctor, as should a temperature of 103°F or higher for a child older than 6 months of age. Your doctor will ask you to report other signs of illness in your child, such as irritability, lethargy or listlessness, poor feeding, diarrhea, reluctance to make eye contact or socialize, poor color, cough, difficulty breathing, or a rash. Signs of illness may be subtle in very young infants, so you'll need to observe carefully.
Any child who looks or acts very ill or has a very high fever should be seen by a doctor immediately. If he can find no obvious cause for the fever, he'll probably order blood tests and other procedures he deems necessary to make sure your child does not have a serious infection.
Whenever your child has a fever, there are a few steps you can take to help cool her down. Remove any excess clothing, maintain a cool environment (about 72°F), give her a sponge bath in lukewarm water, and give her plenty of liquids (for a baby, offer breast milk or formula; for a toddler, water, diluted juice, or other iced drinks are best) because fever can be extremely dehydrating. Ask your doctor if he recommends acetaminophen or ibuprofen (both available over-the-counter in infant drop form) for your baby; they are effective in lowering a fever as well as relieving side effects -- including headache or muscle aches -- that often accompany a temperature over 102°F. Ask your doctor to clarify the correct dosage for each medication, based on your baby's weight. You can expect your child's fever to fall about 2 to 3 degrees within 2 hours of giving an appropriate dose of infant acetaminophen (don't use more than once every 4 to 6 hours) or infant ibuprofen (don't use more than once every 6 to 8 hours). Important: Do not use aspirin to treat fever in children; it has been linked with Reye's syndrome, a rapidly progressive and dangerous illness.