Sore mouth due to chemotherapy

Sore mouth due to chemotherapy

The lining of your child's mouth and throat becomes weak during chemotherapy treatment. This can lead to inflammation and ulcers. Good mouth care will help avoid infection and will make things more comfortable for your child.

Key points to remember

  • a sore mouth and throat are common side effects of chemotherapy treatment
  • the lining of your child's mouth and throat becomes weak - this may lead to inflammation and ulcers
  • good mouth care will help avoid infection and will make things more comfortable for your child
  • make sure your child's toothbrush is clean and replace it every 1 to 2 months

This page is part of a whole section about childhood cancer.

How does chemotherapy affect your child's mouth and throat?

The lining of your child's mouth and throat becomes weak during chemotherapy treatment - this may lead to inflammation and ulcers. This is called mucositis. Mucositis reduces the desire to eat, drink and swallow. It may also lead to septicaemia (bacteria entering the bloodstream). Good mouth care will help avoid infection and will make things more comfortable for your child.

What is good mouth care?

  • brush teeth using a soft-bristled toothbrush and toothpaste at least twice a day - this helps to stop plaque build-up and prevent gum disease
  • make sure your child's toothbrush is clean and replace it every 1 to 2 months
  • before a visit to the dentist, tell the dentist that your child is having chemotherapy
  • tell your doctor if your child is having trouble with their teeth
  • always tell your doctor before you make a dental appointment for your child
  • keep lips moist by using creams often, including after brushing - creams such as lanolin and soft paraffin will protect against drying and chapping

When is mouth soreness likely to happen?

Your child is likely to feel mouth soreness 7 to 10 days after chemotherapy starts. This is the time when the blood cell counts are likely to be lowest, and the lining of the mouth will be weak.

What about eating and drinking?

Make sure your child has a fresh, clean mouth before eating. Swishing with water or a mouthwash may be enough, or you may need to help with gentle teeth cleaning. After that, here are some ideas which may help.

Give soft moist foods

Some examples are custard and yoghurt, scrambled eggs, mornay (cheese-flavoured white sauce), mashed vegetables with butter, ice cream, pasta, custard, rice or baby food.

Keep foods moist by adding extra gravy, sauce, yoghurt, cream or butter.

Give nourishing drinks

Give nourishing drinks that your child can sip slowly.

Some suggestions:

  • milkshakes - full cream milk with added ice-cream, cream or yoghurt and flavouring
  • fruit smoothies - banana or strawberries blended with milk
  • yoghurt smoothies - fruit juice, yoghurt and fresh fruit mixed
  • supplements added to drinks - speak to your child's dietitian

Avoid rough foods and foods that might sting

Avoid giving foods that might sting like citrus juice and very salty or spicy foods.

Avoid giving rough foods like toast, and foods that may need a lot of chewing.

What are the signs of a sore mouth?

If your child can't tell you their mouth is sore, these are the signs to look for:

  • drooling (in younger children)
  • difficulty speaking or opening their mouth
  • refusing food and drink because of pain when eating
  • difficulty swallowing
  • dry or cracked lips
  • pale, rigid gums
  • redness and/or swelling of their gums
  • bleeding gums
  • mouth ulcers

How can you help make mouth care fun?

Involve brothers and sisters in the game of mouth care.

  • role play with a dolly or teddy
  • use praise and encouragement - ask for kisses to smell the sweet, fresh breath
  • play with the swabs, pretending to paint pictures inside your child's mouth
  • encourage independence by allowing younger children to hold the swab, put on the gel etc
All the information in the Childhood cancer section of this website has been written by health professionals who work in the field of paediatric oncology. They have been reviewed by the members of the National Child Cancer Network (NZ). Medical information is authorised by the National Child Cancer Network Clinical Leader.

This page last reviewed 21 May 2018.
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