Stomatitis and related lesions (K12) ICD-10-CM
The K12 code range covers stomatitis and related lesions with 10 ICD-10-CM diagnosis codes. 8 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
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.
- code to identify:
- alcohol abuse and dependence F10
- exposure to environmental tobacco smoke Z77.22
- exposure to tobacco smoke in the perinatal period P96.81
- history of tobacco dependence Z87.891
- occupational exposure to environmental tobacco smoke Z57.31
- tobacco dependence F17
- tobacco use Z72.0
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Codes in the K12 Range 10 codes · 8 billable
- K12 Stomatitis and related lesionsNon-billable
- K12.0 Recurrent oral aphthae
- K12.1 Other forms of stomatitis
- K12.2 Cellulitis and abscess of mouth
- K12.3 Oral mucositis (ulcerative)Non-billable
- K12.30 Oral mucositis (ulcerative), unspecified
- K12.31 Oral mucositis (ulcerative) due to antineoplastic therapy
- K12.32 Oral mucositis (ulcerative) due to other drugs
- K12.33 Oral mucositis (ulcerative) due to radiation
- K12.39 Other oral mucositis (ulcerative)
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the K12 range.
Oral Mucositis
Inflammation of the ORAL MUCOSA.
Stomatitis
INFLAMMATION of the soft tissues of the MOUTH, such as MUCOSA; PALATE; GINGIVA; and LIP.
About the K12 Code Range
These conditions affect the mouth and include recurring sores, inflammation, abscesses, and ulcerative inflammation of the mouth lining.
K12.0 identifies recurring oral sores. K12.1 covers other stomatitis, or mouth inflammation. K12.2 covers mouth cellulitis, or tissue inflammation, and abscess. K12.3 covers ulcerative oral mucositis, or inflammation of the mouth lining with ulcers.
The mucositis subdivisions distinguish unspecified cases, cases due to antineoplastic therapy, other drugs, or radiation, and other cases.
Questions About This Page
How many billable codes are in the K12 range?
Of the 10 codes in this range, 8 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the K12 range classify?
The range classifies stomatitis and related lesions. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
