Causes of mucositis 

Mucositis is usually a side effect of cancer treatment.

Radiotherapy and chemotherapy

Radiotherapy and chemotherapy are very effective treatments for killing cancer cells but can also damage healthy cells, particularly cells in your mucous membrane, which are more vulnerable to damage. The mucous membrane is the soft layer of tissue that lines your digestive system, from the mouth to the anus.

Radiotherapy and chemotherapy damage the DNA of the cells on the lining of your mucous membrane, which damages the cells and prevents them from regenerating.

This causes the layer of tissue that lines your mucous membrane to eventually break down and ulcers will form. Your cancer treatment team will make every effort to limit the damage to your mucous membrane, but it is not always possible to prevent damage occurring.

Biological therapies

Biological therapies, also called targeted therapies, are another type of cancer treatment that can cause oral mucositis.

Some cases are thought to be different from mucositis caused by radiotherapy or chemotherapy, although at the moment they are poorly understood.  

Increased risk

Certain things can increase your risk of developing mucositis, or may increase your risk of mucositis being severe. These include:  

  • being younger – oral mucositis is more severe in young people 
  • smoking
  • drinking alcohol
  • eating spicy foods
  • dehydration
  • having a dry mouth during your treatment – a dry mouth is another side effect of radiotherapy and chemotherapy
  • not looking after your mouth properly before and during treatment – for example, by not brushing your teeth regularly 
  • receiving a higher dose of chemotherapy or being treated with chemotherapy for a long time
  • receiving high-dose radiotherapy to your mouth or neck

Mucositis can also sometimes develop during and after a stem cell transplant (bone marrow transplant). This is because cancer treatments are used in combination with medicines that reduce the effectiveness of your immune system (the body's natural defence against infection and illness) during this procedure.

Page last reviewed: 26/10/2012

Next review due: 26/10/2014