A fever is an increase in the body's temperature. It is usually defined as a temperature of 100.4°F (38°C) or higher. In children older than 3 months, a brief mild or moderate fever generally has no long-term effect, and it usually does not need treatment. In children younger than 3 months, a fever may indicate a serious problem. A high fever in babies and toddlers can sometimes trigger a seizure (febrile seizure). The sweating that may occur with repeated or prolonged fever may also cause a loss of fluid in the body (dehydration).

• Age.
• Time of day.
• Where in the body you take the temperature. Readings may vary if you place the thermometer:
  • In the mouth (oral).
  • In the rectum (rectal). This is the most accurate.
  • In the ear (tympanic).
  • Under the arm (axillary).
  • On the forehead (temporal).

Follow these instructions at home:

Medicines

• Give over-the-counter and prescription medicines only as told by your child's health care provider. Carefully follow dosing instructions from your child's health care provider.
• Do not give your child aspirin because of the association with Reye's syndrome.
• If your child was prescribed an antibiotic medicine, give it only as told by your child's health care provider. Do not stop giving your child the antibiotic even if he or she starts to feel better.

If your child has a seizure:

• Keep your child safe, but do not restrain your child during a seizure.
• To help prevent your child from choking, place your child on his or her side or stomach.
• If able, gently remove any objects from your child's mouth. Do not place anything in his or her mouth during a seizure.

General instructions

• Watch your child's condition for any changes. Let your child's health care provider know about them.
• Have your child rest as needed.
• Have your child drink enough fluid to keep his or her urine pale yellow. This helps to prevent dehydration.
• Sponge or bathe your child with room-temperature water to help reduce body temperature as needed. Do not use cold water, and do not do this if it makes your child more fussy or uncomfortable.
• Do not cover your child in too many blankets or heavy clothes.
• If your child's fever is caused by an infection that spreads from person to person (is contagious), such as a cold or the flu, he or she should stay home. He or she may leave the house only to get medical care if needed. The child should not return to school or day care until at least 24 hours after the fever is gone. The fever should be gone without the use of medicines.
• Keep all follow-up visits as told by your child's health care provider. This is important.

Contact a health care provider if your child:

• Vomits.
• Has diarrhea.
• Has pain when he or she urinates.
• Has symptoms that do not improve with treatment.
• Develops new symptoms.

Get help right away if your child:

• Who is younger than 3 months has a temperature of 100.4°F (38°C) or higher.
• Becomes limp or floppy.
• Has wheezing or shortness of breath.
• Has a febrile seizure.
• Is dizzy or faints.
• Will not drink.
• Develops any of the following:
  • A rash, a stiff neck, or a severe headache.
  • Severe pain in the abdomen.
  • Persistent or severe vomiting or diarrhea.
  • A severe or productive cough.
• Is one year old or younger, and you notice signs of dehydration. These may include:
  • A sunken soft spot (fontanel) on his or her head.
  • No wet diapers in 6 hours.
  • Increased fussiness.
• Is one year old or older, and you notice signs of dehydration. These may include:
  • No urine in 8–12 hours.
  • Cracked lips.
  • Not making tears while crying.
  • Dry mouth.
  • Sunken eyes.
  • Sleepiness.
  • Weakness.

Summary

• A fever is an increase in the body's temperature. It is usually defined as a temperature of 100.4°F (38°C) or higher.
• In children younger than 3 months, a fever may indicate a serious problem. A high fever in babies and toddlers can sometimes trigger a seizure (febrile seizure). The sweating that may occur with repeated or prolonged fever may also cause dehydration.
• Do not give your child aspirin because of the association with Reye's syndrome.
• Pay attention to any changes in your child's symptoms. If symptoms worsen or your child has new symptoms, contact your child's health care provider.
• Get help right away if your child who is younger than 3 months has a temperature of 100.4°F (38°C) or higher, your child has a seizure, or your child has signs of dehydration.