2026 ICD-10-CM Diagnosis Code K12.1Other forms of stomatitis

ICD-10-CM Codes›K00–K95›K00-K14›K12

ICD-10-CM K12.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K12.1 is a billable ICD-10-CM diagnosis code for other forms of stomatitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 157 through 159. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Diseases of mouth; excluding dental, and Nontraumatic dental conditions.

Code Identity

ICD-10-CM Code
K12.1
Billable Status
Yes — Valid for Submission
Code Describes
Other forms of stomatitis
Short Description
Other forms of stomatitis
Same as the full description in the CMS dataset.
Parent Code
K12
Stomatitis and related lesions

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK12Stomatitis and related lesions
This CodeK12.1Other forms of stomatitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Allergic contact stomatitis caused by denture
  • Atrophic mucosa of digestive system organ
  • Atrophic thrush
  • Bleeding of oral mucosa
  • Chronic atrophic candidiasis
  • Chronic ulcerative stomatitis
  • Classical histoplasmosis mucosal ulceration
  • Classical histoplasmosis oral ulceration
  • Contact mucous membrane inflammation
  • Contact stomatitis
  • Coxsackie virus infection of oral cavity
  • Denture stomatitis
  • Drug-induced oral condition
  • Drug-induced oral ulceration
  • Erosion of oral mucosa
  • Erythema multiforme co-occurrent with ulcer of oral mucous membrane
  • Erythema of mucous membrane of mouth
  • Granular stomatitis
  • Hemorrhagic stomatitis
  • Irritant contact stomatitis caused by denture
  • Mucosal vesicle
  • Mucous membrane erythema
  • Nonspecific irritant contact stomatitis
  • Oral erythematous candidiasis
  • Oral mucosal fungal disease
  • Oral mucous membrane inflammation due to denture trauma
  • Oral ulceration caused by cold burn
  • Oral ulceration due to chemical burn
  • Oral ulceration due to thermal burn
  • Oral vesiculoulcerative disease
  • Palatitis
  • Plant awn stomatitis
  • Pyostomatitis vegetans
  • Recurrent ulcer of mouth
  • Stomatitis
  • Stomatitis areata migrans
  • Stomatitis artefacta
  • Stomatitis due to and following radiation therapy
  • Stomatitis medicamentosa
  • Streptococcal infection of mouth
  • Suppurative inflammation of oral soft tissue
  • Traumatic oral hemorrhagic bulla
  • Traumatic oral ulceration
  • Ulcer of buccal mucosa
  • Ulcer of mouth
  • Ulcer of mouth due to immunobullous disease
  • Ulcer of palate
  • Ulcer of skin of face
  • Ulcerative stomatitis
  • Uremic stomatitis
  • Vesicular stomatitis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Stomatitis NOS
  • Denture stomatitis
  • Ulcerative stomatitis
  • Vesicular stomatitis

Type 1 Excludes

  • acute necrotizing ulcerative stomatitis A69.1
  • Vincent's stomatitis A69.1

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Catarrh, catarrhal(acute) (febrile) (infectious) (inflammation)
      • mouth
    • Inflammation, inflamed, inflammatory(with exudation)
      • mouth
    • Stomatitis(denture) (ulcerative)
    • Stomatitis(denture) (ulcerative)
      • catarrhal
    • Stomatitis(denture) (ulcerative)
      • follicular
    • Stomatitis(denture) (ulcerative)
      • malignant
    • Stomatitis(denture) (ulcerative)
      • membranous acute
    • Stomatitis(denture) (ulcerative)
      • septic
    • Stomatitis(denture) (ulcerative)
      • vesicular
    • Ulcer, ulcerated, ulcerating, ulceration, ulcerative
      • buccal (cavity) (traumatic)
    • Ulcer, ulcerated, ulcerating, ulceration, ulcerative
      • oral mucosa (traumatic)
    • Ulcer, ulcerated, ulcerating, ulceration, ulcerative
      • palate (soft)
    • Ulcer, ulcerated, ulcerating, ulceration, ulcerative
      • stomatitis

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DEN001
Any dental condition including traumatic injury
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG003
Diseases of mouth; excluding dental
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Vesicular Stomatitis

    a viral disease caused by at least two distinct species (serotypes) in the vesiculovirus genus: vesicular stomatitis indiana virus and vesicular stomatitis new jersey virus. it is characterized by vesicular eruptions on the oral mucosa in cattle, horses, pigs, and other animals. in humans, vesicular stomatitis causes an acute influenza-like illness.

  • Vesicular stomatitis Indiana virus

    the type species of vesiculovirus causing a disease symptomatically similar to foot-and-mouth disease in cattle, horses, and pigs. it may be transmitted to other species including humans, where it causes influenza-like symptoms.

  • Vesicular stomatitis New Jersey virus

    a species of vesiculovirus causing vesicular stomatitis primarily in cattle, horses, and pigs. it can be transmitted to humans where it causes influenza-like symptoms.

  • Vesiculovirus

    a genus of the family rhabdoviridae that infects a wide range of vertebrates and invertebrates. the type species is vesicular stomatitis indiana virus.

  • Gingivitis, Necrotizing Ulcerative

    an acute or chronic gingivitis characterized by redness and swelling, necrosis extending from the interdental papillae along the gingival margins, pain; hemorrhage, necrotic odor, and often a pseudomembrane. the condition may extend to the oral mucosa; tongue; palate; or pharynx. the etiology is somewhat unclear, but may involve a complex of fusobacterium nucleatum along with spirochetes borrelia or treponema.

  • Noma

    a severe gangrenous process occurring predominantly in debilitated and malnourished children, especially in underdeveloped countries. it typically begins as a small vesicle or ulcer on the gingiva that rapidly becomes necrotic and spreads to produce extensive destruction of the buccal and labial mucosa and tissues of the face, which may result in severe disfigurement and even death. various bacteria have been implicated in the etiology. (dorland, 27th ed)

  • Stomatitis

    inflammation of the soft tissues of the mouth, such as mucosa; palate; gingiva; and lip.

  • Stomatitis, Aphthous

    a recurrent disease of the oral mucosa of unknown etiology. it is characterized by small white ulcerative lesions, single or multiple, round or oval. two to eight crops of lesions occur per year, lasting for 7 to 14 days and then heal without scarring. (from jablonski's dictionary of dentistry, 1992, p742)

  • Stomatitis, Denture

    inflammation of the mouth due to denture irritation.

  • Stomatitis, Herpetic

    stomatitis caused by herpesvirus hominis. it usually occurs as acute herpetic stomatitis (or gingivostomatitis), an oral manifestation of primary herpes simplex seen primarily in children and adolescents.

  • Tumor Protein 63|CUSP|Chronic Ulcerative Stomatitis Protein|Keratinocyte Transcription Factor KET|TP63|Transformation-Related Protein 63|Tumor Protein p73-Like|p40|p51|p63|p73L

    tumor protein 63 (680 aa, ~77 kda) is encoded by the human tp63 gene. this protein plays a role in the mediation of both transcription and limb morphogenesis.

  • Ulcerative Stomatitis

    inflammation of the mouth mucosa associated with the presence of ulcers.

Patient EducationClinical

Mouth Disorders

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

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K12.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
528.09 Stomatits & mucosits NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K12.1Overview

Is K12.1 (Stomatitis and related lesions) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other forms of stomatitis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K12.1 group to?

When other forms of stomatitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 157, 158, 159, with relative weights from 0.7085 to 1.7168 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K12.1?

Under the General Equivalence Mappings, other forms of stomatitis converts to ICD-9-CM 528.09 (stomatits & mucosits NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.