Some kinds of chemotherapy and radiation treatments can cause oral mucositis. You might also hear this condition called ulcerative oral mucositis, mouth sores, and mouth ulcers.

About 40 percent of people undergoing regular cancer therapy will get oral mucositis. Up to 75 percent of people with high-dose chemotherapy and up to 90 percent of people getting both chemotherapy and radiation treatments may get this condition.

The Oral Cancer Foundation advises that if you’re getting treatment for cancer, you may have a higher risk of oral mucositis if you:

  • smoke or chew tobacco
  • drink alcohol
  • are dehydrated
  • have poor nutrition
  • have poor dental health
  • have diabetes
  • have kidney disease
  • are living with HIV
  • are female (as it’s more common in women than men)

Children and younger adults are more likely to get oral mucositis but may also heal faster than older adults experiencing it. This is because younger people shed and gain new cells faster.

Other causes of oral mucositis include:

  • Thrush: This infection occurs from yeast overgrowth in the mouth and on the tongue. It’s also known as oral thrush and oral candidiasis. Thrush looks like small white bumps on the tongue and inside the mouth.
  • Stomatitis: This is a sore or infection on the lips or inside the mouth. Two main kinds are cold sores and canker sores. Stomatitis may be caused by the herpes virus.
  • Hand, foot, and mouth disease: This highly contagious viral infection is caused by the coxsackievirus. Hand, foot, and mouth disease causes sores in the mouth and rashes on the hands and feet. It’s most common in children under age 5.

A sore mouth can make it difficult for you to eat or drink. In some cases, your doctor may recommend slowing down or stopping treatment for a little while to help the sores heal.

Oral mucositis from chemotherapy or radiation treatment can last from 7 to 98 days. Variables such as the type of therapy and therapy frequency have an impact on oral mucositis symptoms, intensity, and length of time.

After therapy is completed, sores from mucositis typically heal in two to four weeks.

Mouth sores can happen anywhere in the mouth, including the:

  • inner part of the lips
  • tongue
  • gums
  • inside of the cheeks or sides of the mouth
  • roof of the mouth

Oral mucositis can cause:

  • pain
  • discomfort or burning
  • swelling
  • bleeding
  • a sore throat
  • sores on the mouth, tongue, and gums
  • a red or shiny mouth and gums
  • difficulty eating and tasting food
  • difficulty chewing
  • difficulty swallowing
  • difficulty talking
  • a bad taste in the mouth
  • thicker mucus and saliva
  • white patches or pus

A very serious case of oral mucositis is called confluent mucositis. Mucositis can lead to:

  • mouth infection
  • a thick white coating in the mouth
  • dead tissue in some parts of the mouth
  • poor nutrition and weight loss

Your doctor may recommend one or a combination of several treatments for oral mucositis.

These include:

Magic mouthwash is one prescription treatment that might be mixed by a pharmacist on-site with medications that address different aspects of the condition.

Q. Is it possible to prevent oral mucositis or mouth ulcers?

A. To a certain degree there does appear to be some promising research that may soon provide definitive guidelines for prevention of mucositis caused by chemotherapy or radiation therapy. Studies have been done involving keratinocyte growth factor medications, anti-inflammatory medications, antimicrobial medications, laser therapy, and cryotherapy. In each of these categories, some studies have found ways to decrease the incidence of mucositis while undergoing cancer treatment. More research must be done to come up with reliable recommendations. — J. Keith Fisher, MD

Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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If you’re getting cancer treatment, talk to your doctor about how to help prevent a sore mouth.

You can speak to a nutritionist or dietitian about the best foods to eat while you have mouth sores.

Regular and gentle dental care habits like daily brushing, flossing, and alcohol-free mouthwashes are also helpful.

Your doctor may recommend other treatments or a combination of treatments for oral mucositis.