When your child appears ill, you probably first feel her forehead to see if she feels warm and may have a fever. Although observing how sick your child looks and acts is the best measure of how sick she is, her temperature can be an important piece of information for you and your doctor.

What are the types of thermometers?

The most common types of thermometers are:

• Plastic digital thermometer: It is inexpensive, accurate, and takes approximately one minute to register the temperature. It can be used to take an oral (mouth), axillary (underarm) or rectal (bottom) temperature.
• Ear thermometer: It is more expensive and not quite as accurate—the temperature reading can vary a little depending on the positioning of the thermometer in the child’s ear—but it is generally adequate. The ear thermometer has the advantage of giving a quick temperature reading within seconds.
• Glass mercury thermometer: This should not be used. If it breaks, it can leak toxic mercury vapor. Your local pharmacy may allow you to trade your old mercury thermometer for a new digital one. Otherwise, take your mercury thermometers to a hazardous waste collection center, or call your local poison control center or fire department to ask the safest way to dispose of them.
• Other newer types of thermometers include a pacifier thermometer (which a baby sucks on) and a temporal artery thermometer (which is rolled across a child’s forehead). These thermometers are currently being evaluated for accuracy. Ask your doctor for advice about them.
  
  How do you take a child’s temperature?
  
  How you take your child’s temperature depends on your child’s age, your type of thermometer, and your comfort level:
  
  
• For infants and toddlers: You can take their temperature with the ear thermometer, or with a plastic digital thermometer under the arm or rectally. Although the rectal temperature is considered most accurate, it can be uncomfortable for some children and it exposes you more to your child’s germs.
• For children over 3 years: You can take their temperature with the ear thermometer, or with a plastic digital thermometer under the arm or in the mouth, if they can cooperate.
• Rectal:
  
• Clean the tip of the thermometer with soap and cool water.
• Put a small amount of lubricant (such as petroleum jelly) on the tip, and turn on the thermometer.
• Lay your child belly down across your lap with his bottom exposed.
• Gently insert the thermometer ½ to 1” into his anus. Hold the thermometer in place by cupping your hand over your baby’s bottom.
• When you hear the beep, remove and read the thermometer.
• Turn off the thermometer. Wash the thermometer and your hands with soap and warm water.
• Oral:
  
• Clean the tip of the thermometer with soap and cool water.
• Turn on the thermometer and place the tip under your child’s tongue toward the back of her mouth. (If your child has eaten or drunk anything cold, wait a while before taking the temperature.)
• When you hear the beep, remove and read the thermometer.
• Turn off the thermometer. Wash the thermometer and your hands with soap and warm water.
• Ear:
  
• Cover the thermometer with a fresh plastic tip.
• With one hand, hold your child’s ear steady.
• With the other hand, gently insert the thermometer into your child’s ear canal until you get a tight seal.
• Press the start button, and read the temperature displayed.
• Discard the used plastic tip.
• Underarm (axillary):
  
• Place the tip of the thermometer under your child’s armpit, between the bare skin of the arm and chest.
• Hold her arm tightly against her chest.
• When you hear the beep, remove and read the thermometer.
• What does the temperature reading mean?
  
  Temperature readings differ depending on how you take your child’s temperature. The closer the thermometer is to the inside of the body, the warmer the temperature it records. The following temperatures are roughly equivalent:
  
  
• Axillary temperature of 100 degrees F.
• Oral temperature of 101 degrees F.
• Rectal temperature of 102 degrees F.
• A fever is when the body temperature is higher than normal. Although we say that normal body temperature taken orally is 98.6 degrees F. (37 degrees C.), this is just the average. In fact, normal body temperature can range from approximately 97 to 100 degrees F. (36- 37.8 degrees C.) Body temperature is usually lower in the morning and higher in the late afternoon and evening. Fevers can be described as low-grade (100-102 degrees), moderate (102-104 degrees) and high (above 104 degrees). If a child has a temperature of 99 degrees F., it would not be considered a fever.
  
  How often should you take your child’s temperature?
  
  The best way to tell how sick your child is—and whether he’s getting better or worse —is by observing how he looks and acts. It is not necessary, and only bothers your child, to take frequent temperatures. Unless the doctor recommends otherwise, it is probably sufficient just to take your child’s temperature once in the morning and the evening, or when his symptoms change. If your child is sleeping well during the daytime or at night, don’t awaken him to take a temperature. Getting rest is far more important to his recovery. What should you do if your child has a fever? No matter what your child’s temperature is, he is likely to be only mildly ill if he is still alert, comfortable, playing, and eating and drinking well; and he may be more seriously ill if he is listless, irritable, and refusing to eat or drink. See the article, “Fevers: What You Need to Know” for information about whether and how to treat fevers, and when to call the doctor.