A fever is a body temperature that is higher than normal. It usually means there is an abnormal process occurring in the body. Exercise, hot weather, and common childhood immunizations can also make body temperature rise.

What causes a fever?

A fever is not an illness by itself. Rather it is a symptom that something is not right within the body. A fever does not tell you what is causing it, or even that a disease is present. It may be a bacterial or viral infection. Or, it could be a reaction from an allergy to food or medication. Becoming overheated at play or in the sun can also result in fever.

What are the symptoms of a fever?

Normal body temperature ranges from 97.5°F to 98.9°F (36.4°C to 37.2°C). It tends to be lower in the morning and higher in the evening. Most health care providers consider a fever to be 100.4°F (38°C) or higher. High fevers may bring on seizures or confusion in children. It's not how high the temperature is, but how fast the temperature goes up that causes a seizure.

A fever has other symptoms besides a higher-than-normal temperature. These are especially important when caring for babies, young children, and disabled people. Signs that mean fever include:

  • Flushed face
  • Hot, dry skin
  • Low output of urine, and dark urine
  • Not interested in eating
  • Constipation or diarrhea
  • Vomiting
  • Headache
  • Aching all over
  • Nausea

How is a fever diagnosed?

The best way to diagnose a fever is to take a temperature with a thermometer. There are several types of thermometers, including the following:

  • Digital thermometer (oral, rectal, or under the armpit)
  • Ear thermometer (not recommended for babies younger than three months of age)

How is a fever treated?

You can treat a fever with acetaminophen or ibuprofen in dosages advised by your health care provider. Switching between giving acetaminophen and ibuprofen can cause medication errors and may lead to side effects. Never give aspirin to a child or young adult who has a fever.

A lukewarm bath may reduce the fever. Alcohol rubdowns are no longer recommended.

Call your health care provider for guidance anytime you are uncomfortable with the conditions of the fever, and remember to contact your health care provider any time temperature spikes quickly or persists despite treatment.

When should I call my health care provider?

Call your health care provider right away for a fever in a baby younger than three months old.

Call right away if any of the following occur with a fever:

  • Seizure
  • Feeling dull or sleepy
  • Irregular breathing
  • Stiff neck
  • Confusion
  • Purple spotted rash
  • Ear pain (a child tugging on his or her ear)
  • A sore throat that persists
  • Vomiting
  • Diarrhea
  • Painful, burning or frequent urination

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