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When Your Child Has a Fever

The body's normal temperature is 98.6°F (37°C). When the body's temperature rises to 100.4°F (38°C) or higher, it is a fever. Most health care professionals agree that a fever by itself is not an illness, but a symptom of an underlying problem.

Most fevers in children are due to common viral illnesses. Fevers can be a positive sign that the body is fighting an infection because fever stimulates certain defenses, such as white blood cells, which attack and destroy invading bacteria. A fever, however, can cause discomfort, increase the need for fluids and make heart rate and breathing faster.

Fevers can be a sign of a serious problem, such as pneumonia,meningitis, kidney infection, or other dangerous infection.. It's important to be attuned to other symptoms the child is experiencing such as changes in eating habits, vomiting or diarrhea, difficulty breathing, tugging or complaining about ears, or changes in skin color.

Even a slight fever—or a slightly lower temperature than normal—in an infant less than 3 months old can indicate a problem. If a child younger than 3 months has a rectal temperature of 100.4° F (38°C) or higher, you should call the doctor immediately.

In older infants and young children, a fever is any temperature of 100.4°F (38°C) or higher.

If you think your child has a fever, take his or her temperature with a digital thermometer. (Do not use mercury thermometers, because they are potentially dangerous.)  

Digital thermometers can be:

  1. Multi-use (can be used under the tongue, in the armpit, or in the rectum. Label the thermometer if it is to be used in the rectum so that it is not later used orally.

  2. Temporal artery (rubbed over the forehead)

  3. Tympanic (placed in the ear canal opening)

  4. Pacifier (some reports say that these may be less reliable)

When to call a doctor

  • For any fever in a child that is newborn to 3 months, call the doctor immediately. In young infants, fever is a major concern because their immune system is immature.

  • For an older child with a fever, watch the child carefully for changes in behavior, and consider the child's age and health history to determine if and when to call your doctor.

  • For a child younger than 2 years of age who has had a fever for more than 24-hours, call your doctor.

    For a child 2 years of age or older whose fever persists more than 3 days, call your doctor.

  • If your child has a fever and looks very ill or is very fussy or lethargic (very sleepy), call your doctor.

  • If you child has a stiff neck, severe headache, or seizure, call your doctor.

You know your child best. If your child is not acting as you would expect or you are worried that your child may have a serious illness causing his fever, always call your doctor for advice.

Where to take a temperature

  • In infants younger than 3 months old, a screening temperature can be taken in the armpit, but if the temperature is higher than 99 °F (37.2°C), then a rectal temperature should be taken. If the rectal temperature is 100.4°F (38°C) or higher, the baby needs to be seen immediately.

  • In children under 3 years of age, a temporal artery thermometer or rectal thermometer may be used. Tympanic (ear) thermometers may be used in children older than 6 months.

  • In children ages 4 and older, oral, temporal artery, or tympanic thermometers may be used.

Taking a rectal temperature

  • Use a lubricating jelly to lubricate the tip of the thermometer. (Check the manufacturer's instructions to see whether they recommend a water-soluble jelly or petroleum jelly.)

  • Place the child across your lap, making sure to support his head. You can also lay him on the changing table or other firm surface.

  • Hold the baby still by pressing the palm of one hand on his lower back.

  • With the other hand, insert the thermometer one-half inch to one inch into the rectum. Stop immediately if the thermometer meets resistance.

  • Hold the thermometer between your second and third fingers and cup your hand around the child's rear. As you hold the thermometer in place, calm the child by speaking softly to him.

  • Keep the thermometer in place until you hear the signal or beep that it is ready. Write down the temperature, the date and time of day.

Treating a fever

  • NEVER give children aspirin to treat a fever. Aspirin has been linked to Reye syndrome, a rare but potentially serious illness that affects the nervous system and can be debilitating or even fatal in children.

  • You only need to treat the fever if your child appears uncomfortable or is bothered by the fever. Fever may actually help the body fight the infection.

  • Acetaminophen and ibuprofen are the two medications for children that help fight fever. Children less than 6 months old should not be given ibuprofen unless directed by your doctor. Read the instructions on the package or ask your doctor to be sure you give appropriate doses. Do not give more than the recommended dose of acetaminophen.

  • Bathing your child with lukewarm water will help bring down fever. Never use cold water or alcohol to bathe your child because it may cause shivering and actually increase the temperature.

  • Dress a child in light, comfortable clothing.

  • Increase fluid intake to prevent dehydration.