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Mouth Sores with Cancer

Why are Mouth Sores Common with Cancer?

When your child refuses to eat or drink, has trouble swallowing, or says his mouth hurts or is sore, your child may have mouth sores. You may be able to see red, raw areas or bleeding from the gums, lips or the inside of the mouth and down the throat.

Mouth sores are a common side effect of some of the cancer treatment drugs your child may be receiving. The sores can change your child's usual eating habits and may lead to an infection. The lining of the mouth and digestive system breaks down and ulcers form. This can be very painful. Patients can also experience abdominal pain or diarrhea.

As the white blood cell count returns to normal, the ulcers heal and the pain goes away. This can take from a few days to a few weeks, depending on the situation.

Treatment for Mouth Sores

  • Clean your child's mouth after meals and before going to bed using soft materials, such as toothettes or cotton swabs.
  • Your child's doctor may recommend mouth rinses, such as nystatin, Biotene or Peridex. The doctor or nurse practitioner will give you specific instructions for use of these mouth rinses.
  • Keep your child's lips lubricated with petroleum jelly (Vaseline or Aquaphor) to prevent cracking.
  • Your child’s doctor or nurse practitioner may also recommend a mouthwash that can help numb the area where there are mouth sores, such as magic mouthwash.
  • Your child may find it helpful to eat cold foods such as popsicles.

Call Your Child's Doctor If:

  • Mouth or throat pain so severe your child cannot eat, drink, or sleep
  • A fever of 100.4 F (38 C) or higher
  • Bleeding from the sores

Last Updated 11/2021

Reviewed By Jill Melchers, MSN, APRN, CNP