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Fever in Infants

November 24, 2020

Fever is very common in children under 12 months of age, and is usually a sign that the body is fighting an infection.

The normal body temperature is 98.6F, or 37C. Doctors generally say that there is a fever when the temperature is 100.4F (38C) or higher.

The best way to take an infant's temperature is rectally with a digital thermometer (never use a glass mercury thermometer). Taking the temperature under the arm, or using an ear thermometer, is less exact.

If your baby has a fever, this guide can help you think about what might be causing it and help you decide if and when you should call the doctor. Please note that this is not meant to take the place of calling or visiting your doctor. If your child has a chronic illness such as sickle cell anemia, or is being treated for any serious illness, you should not use this guide but instead call your doctor immediately.

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Fever can sometimes be a sign of a dangerous illness.

Does any of the following describe your baby?

  • He has a high fever (greater than 102 F or 39C).

  • He is very irritable.

  • He is very weak or much sleepier than usual.

  • He has dark red spots on his skin that don't get paler when you press on them.

  • He is having trouble breathing (breathing very quickly, labored breathing, sucking in around his ribs).

  • His skin looks pale or bluish.

  • He is vomiting bloody, black, or green liquid.

  • His stool is bloody or black.

  • He has gone more than six hours without a wet diaper.

  • He is drooling excessively and having a lot of trouble swallowing.

Yes, one of these describes my baby.

No, none of those describe my baby.

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