What does ICD-10 code K12 mean?

ICD-10 code K12 is the standardized code used for stomatitis and related lesions in medical records and coding systems.

When is ICD-10 code K12 used?

Doctors, hospitals, and insurers may use ICD-10 code K12 when recording stomatitis and related lesions in a standardized format. This entry may also act as a broader category that points toward more specific child codes.

Does ICD-10 code K12 confirm a diagnosis?

No. A code helps standardize documentation and claims, but it should not be read as a substitute for a clinician's full assessment.

ICD10

ICD-10 Code K12: Stomatitis and related lesions

Name: ICD-10 Code K12: Stomatitis and related lesions
Creator: HealthAssure Clinical Team
Published: 2026-05-21T06:15:17.023Z

K12 is an ICD-10 diagnosis entry used to group records related to Stomatitis and related lesions. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).

When is it used?

May be used when a clinician documents stomatitis and related lesions in a patient's medical record.
May appear in hospital records, claims, referrals, and clinical documentation.
This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

A code alone does not explain severity, treatment plan, or outcome.
A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
This entry may represent a broader category rather than the most specific billable code.

Code hierarchy

chapter

11Diseases of the digestive system (K00-K95)

block

K00-K14Diseases of oral cavity and salivary glands

currentK00-K14

Official coding notes

Applicable to

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)

Excludes1 (do not code together)

cancrum oris (A69.0)
cheilitis (K13.0)
gangrenous stomatitis (A69.0)
herpesviral [herpes simplex] gingivostomatitis (B00.2)
noma (A69.0)

Use 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)

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Related specialists

GastroenterologistGeneral Physician

Sibling codes

K00Disorders of tooth development and eruption K01Embedded and impacted teeth K02Dental caries K03Other diseases of hard tissues of teeth K04Diseases of pulp and periapical tissues K05Gingivitis and periodontal diseases K06Other disorders of gingiva and edentulous alveolar ridge K08Other disorders of teeth and supporting structures K09Cysts of oral region, not elsewhere classified K11Diseases of salivary glands K13Other diseases of lip and oral mucosa K14Diseases of tongue

Coding guidelines

Compatibility

Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.

Legacy codes

K12

Replacement codes

K12.0 — Recurrent oral aphthaeK12.1 — Other forms of stomatitisK12.2 — Cellulitis and abscess of mouth

Common synonyms

Stomatitis and related lesions

Frequently asked questions

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.