What causes oral mucositis?

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Last updated: June 27, 2025View editorial policy

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From the Guidelines

Oral mucositis is primarily caused by cancer treatments, specifically chemotherapy and radiation therapy to the head and neck region, as evidenced by the most recent and highest quality study 1. These treatments damage the rapidly dividing cells lining the mouth and throat, leading to inflammation, ulceration, and painful sores. High-dose chemotherapy drugs like 5-FU, capecitabine, irinotecan, or tegafur are particularly associated with mucositis development, as they can lead to a clinically significant incidence of alimentary tract mucositis 1. Radiation therapy causes cumulative damage to oral tissues, with severity increasing as treatment progresses. Biological factors also play a role, including the release of pro-inflammatory cytokines, oxidative stress, and bacterial colonization of damaged tissues. Individual risk factors include poor oral hygiene, existing dental problems, smoking, alcohol use, and certain genetic predispositions that affect how the body processes cancer treatments. Additionally, immunosuppression from cancer or its treatment can worsen mucositis by reducing the body's ability to heal damaged tissues and increasing susceptibility to secondary infections that exacerbate the condition. Some key points to consider in the management of oral mucositis include:

  • The use of palifermin, cryotherapy, and low-level laser therapy (LLLT) as preventive measures in certain cases 1
  • The importance of oral hygiene and dental care in preventing and managing mucositis
  • The need for individualized treatment plans based on the specific cause and severity of mucositis, as well as the patient's overall health status. It is essential to prioritize the most recent and highest quality evidence when making decisions about the management of oral mucositis, as this will help to minimize morbidity, mortality, and improve quality of life for patients with this condition 1.

From the Research

Causes of Oral Mucositis

Oral mucositis is a common complication among cancer patients, and its causes can be attributed to various factors, including:

  • Radiation therapy to the head and neck area 2, 3, 4
  • Chemotherapy agents 2, 3, 5, 6, 4
  • Hematopoietic stem cell transplantation 2
  • Type, dosage, and schedule of radiation or chemotherapy 4
  • Patient-related factors, such as poor oral hygiene and pre-existing oral conditions 4

Risk Factors

The risk of developing oral mucositis is increased in patients who:

  • Receive high-dose chemotherapy or radiation therapy 3, 5, 6
  • Have a history of oral mucositis 6
  • Have poor oral hygiene or pre-existing oral conditions 4
  • Undergo hematopoietic stem cell transplantation 2

Underlying Mechanisms

The development of oral mucositis involves multiple cellular processes, including:

  • Damage to the epithelium and submucosa 6
  • Inflammation and infection 4
  • Impaired healing and tissue repair 5, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Methylene Blue for the Treatment of Intractable Pain Associated with Oral Mucositis.

Pain practice : the official journal of World Institute of Pain, 2017

Research

Oncological-Therapy Related Oral Mucositis as an Interdisciplinary Problem-Literature Review.

International journal of environmental research and public health, 2020

Research

Treatment of oral mucositis due to chemotherapy.

Journal of clinical and experimental dentistry, 2016

Research

Cancer therapy-related oral mucositis.

Journal of dental education, 2005

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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