2021 ICD-10-CM Code K12.33

Oral mucositis (ulcerative) due to radiation

Version 2021
Billable Code

Valid for Submission

K12.33 is a billable diagnosis code used to specify a medical diagnosis of oral mucositis (ulcerative) due to radiation. The code K12.33 is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.

The ICD-10-CM code K12.33 might also be used to specify conditions or terms like mucositis following radiation therapy or radiation-induced mucositis of oral mucous membranes.

ICD-10:K12.33
Short Description:Oral mucositis (ulcerative) due to radiation
Long Description:Oral mucositis (ulcerative) due to radiation

Code Classification

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code K12.33:


Use Additional Code

Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code K12.33 are found in the index:

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Convert K12.33 to ICD-9 Code

The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code K12.33 its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.

Information for Patients


Mouth Disorders

Your mouth is one of the most important parts of your body. It has many different functions. It allows you to

Any problem that affects your mouth can make it hard to eat, drink, or even smile. Some common mouth problems include

Treatment for mouth disorders varies, depending on the problem. If a mouth problem is caused by some other disease, treating that disease can help. It is also important to keep your mouth clean and healthy by brushing, flossing, and not using tobacco.


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Radiation Therapy

Also called: Brachytherapy, Radiotherapy

Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from spreading. About half of all cancer patients receive it. The radiation may be external, from special machines, or internal, from radioactive substances that a doctor places inside your body. The type of radiation therapy you receive depends on many factors, including

Radiation therapy can damage normal cells as well as cancer cells. Treatment must be carefully planned to minimize side effects. Common side effects include skin changes and fatigue. Other side effects depend on the part of your body being treated.

Sometimes radiation is used with other treatments, like surgery or chemotherapy.

NIH: National Cancer Institute


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Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)