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Symptom Checker

Fever in Babies Under 12 Months

A fever is a body temperature that is higher than normal. In babies, fever is especially important because very young infants can become seriously ill with few other obvious symptoms.

Viral infections and bacterial infections are common causes of fever in babies. Vaccines and other inflammatory or medical conditions can also raise a baby’s temperature.

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AAP Guide to Fever in Babies Under 12 Months

The AAP guide below explains what counts as a fever, what to watch for, and when your baby needs medical care.

AAP Symptom CheckerFever under 12 months

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Symptom CheckerFever under 12 months New tab

When to see a doctor

Contact your pediatrician or another healthcare professional if:

  • Your baby is younger than 3 months and has a temperature of 100.4°F (38°C) or higher.
  • Your baby drinks much less than usual or has fewer wet diapers.
  • Your baby is unusually sleepy, irritable or difficult to comfort.
  • The fever persists, returns or comes with other symptoms that concern you.

Call 911 or get emergency care if:

  • Your baby has severe trouble breathing.
  • Your baby is very difficult to wake or does not respond normally.
  • Your baby has a seizure or develops blue or gray lips or face.
  • You think your baby has a life-threatening emergency.

Talk to a nurse now, at any hour

When can my child be seen

Be seen today.

Every office keeps same-day appointments for illness and injury.

This evening or at the weekend.

Most offices run After Hours Care, by appointment rather than walk-in.

If you are worried, call. We would rather answer a question that turns out to be nothing.

More on fever and infection

See the rest of this group and all 164 symptoms