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The signs of infection


Many St. Jude patients are at risk for infection. Treatments, such as chemotherapy (cancer-fighting drugs) and radiation therapy, can also affect the immune system. At times your child will not be able to fight infection well and could become seriously ill as a result. It is important to watch for signs of an infection, so it can be treated quickly.

Signs of infection

Whether you are at St. Jude or at home, tell the doctor right away if you notice these signs that might mean your child has an infection:

  • Fever for patients older than 3 months:
    • An oral (by mouth) temperature of 100.9 degrees F (38.3 degrees C) or higher;
    • An oral temperature of 100.4 degrees F (38.0 degrees C) or higher that persists for one hour;
    • An under-the-arm (axillary) temperature of 99.9 degrees F (37.7 degrees C); or
    • An under-the-arm temperature of 99.4 degrees F (37.4 degrees C) or higher that persists forone hour.
  • Fever for patients younger than 3 months:
    • An under-the-arm (axillary) temperature of 99.4 degrees F (37.4 degrees C) or higher.
  • Fever is usually a sign of infection; it may be the only sign. (To learn more, see “Do you know…How to take a temperature.”)
  • Coughing or fast breathing
  • Blisters, rash, or skin sores
  • Runny nose
  • Earache
  • Loose bowels
  • Sore throat
  • Stomach pain
  • Sores or pain around the rectum
  • Headache and stiff neck

If your child develops an infection while his white blood cell count is low, the usual warning signs such as pus (or drainage), redness, and swelling may not always be present. A tiny bump could mean something is wrong.

If you have more questions about the signs of infection or about how to protect your child from infection, talk to your doctor or nurse.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

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