Fact Sheets : Fever In Children

What causes fever?

Fever is a symptom and not a diagnosis or a medical condition. The most common cause of a fever in children is an infection, mostly viral but in some cases bacterial. One of the challenges in evaluating children with fever is trying to determine the cause, or at least to making sure it is not due a bacterial. This distinction is important, as viral infections do not need antibiotic treatment, but bacterial infections usually do. In general, the younger the child, the sicker looking the child and/or the longer the fever persists, the higher the chance is of a bacterial infection. Also, as important as the degree of fever is how a febrile child generally looks; For example, a sick looking child with a low fever may be more ill than a very well, active child with a higher fever.

What is the normal range of body temperature?

The ranges of normal body temperature are:

Measured rectally:36.6º - 38º (C), or 97.9º - 100.4º (F)

By mouth: 35.5º to 37.5º (C), or 95.9º - 99.5º (F)

Axillary(armpit): 34.7º to 37.3º (C), or 94.5º - 99.1º (F)

What body temperature is considered to be fever?

The normal body temperature is usually 98.6º F (37º C). A child is considered to have a fever depending on how the temperature is taken. If the temperature is over: 100.4º F(38º C) rectally, 100º F(37.8º C) orally or 99º F(37.2º C) axillary(armpit), the child is considered to have a fever.

How can the fever be lowered?

Lowering the temperature with Acetaminophen (Tylenol or Tempra) can help your child feel better and less irritable. It usually takes up to 60-90 minutes for the fever to go down. Aspirin (acetylsalicylic acid) should not be used. If Acetaminophen doesn't bring the temperature down, then the child could be given a luke-warm sponge bath. Do not use cool or cold compresses or baths and never use alcohol sponging. If your child is on antibiotics, it generally takes 48 hours before they start to work. During this time, Acetaminophen may still be given to control the fever.

When to call your doctor about your child's fever?

Worrisome or alarm signs:

  • If the fever is higher than 103º F(39.5 º C) rectal or...
  • If your child appears unwell or unusually ill(this applies even when there is no fever) or...
  • Persistent fever(more than 3-4 days) or...
  • If your child is less than 6 months of age