ICD-10 Logo
ICDxICD-10 Medical Coding
ICD-10 Logo
ICDxICD-10 Medical Coding
ICD 10 CodesDiagnoses
ICD 10 CodesDiagnoses
ICD-10 Logo
ICDxICD-10 Medical Coding

Comprehensive ICD-10-CM code reference with AI-powered search capabilities.

© 2025 ICD Code Compass. All rights reserved.

Browse

  • All Chapters
  • All Categories
  • Diagnoses

Tools

  • AI Code Search
ICD-10-CM codes are maintained by the CDC and CMS. This tool is for reference purposes only.
v1.0.0
ICD-10 Guide
DiagnosesAphthous Stomatitis

Aphthous Stomatitis

ICD-10 Coding for Aphthous Stomatitis(K12.0, K12.1)

PRIMARY SPECIALTYPrimary Care
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Aphthous Stomatitis?
Essential facts and insights about Aphthous Stomatitis

Key Clinical Considerations:

  • Presence of painful, recurrent oral ulcers (aphthous ulcers) typically located on non-keratinized mucosa.
  • Ulcers are usually round or oval with a gray or whitish center and a red halo.
  • No systemic symptoms such as fever or malaise are typically present.
  • Physical examination may reveal multiple ulcers, often measuring 2-10 mm in diameter.
  • Severity can be classified based on frequency of episodes and size of ulcers: minor (less than 1 cm), major (greater than 1 cm), and herpetiform (multiple small ulcers).

Clinical Information

Clinical Criteria & Documentation Requirements

  • Document the presence, size, and location of ulcers in the oral cavity.
  • Use specific terminology such as 'aphthous ulcer' or 'canker sore' in the medical record.
  • Examples include: 'Patient presents with multiple aphthous ulcers on the buccal mucosa.'
  • Document medical necessity for treatment, including pain management and dietary modifications.
  • Quality measures may include tracking frequency of ulcer episodes and response to treatment.

Coding Guidelines

Usage Guidelines & Examples

  • Use K12.0 for recurrent aphthous stomatitis and K12.1 for other forms of stomatitis.
  • Do not use these codes for ulcers caused by infections, trauma, or systemic diseases.
  • K12.8 (other specified disorders of lip and oral mucosa) may be used for related conditions.
  • Common errors include misclassifying ulcers due to viral infections as aphthous stomatitis.
  • In complex cases, consider the patient's history and other oral conditions before code selection.

Code Exclusions

Important Exclusions

  • Exclude codes for ulcers due to infections (e.g., herpes simplex) or systemic diseases (e.g., Crohn's disease).
  • Use appropriate codes for these excluded conditions, such as B00.1 for herpes simplex.
  • Conditions are excluded because they have different underlying causes and treatment protocols.
  • Common mistakes include coding aphthous stomatitis when the ulcers are due to another etiology.
  • Related but distinct conditions include oral lichen planus and pemphigus vulgaris.

Related ICD-10 Codes

Primary Codes
K12.0
Recurrent aphthous stomatitis
K12.1
Other forms of stomatitis
Ancillary Codes
Z77.29
B12
are documented.
F52.8
Differential Codes
B00.2
B37.0

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Primary Care

Specialty Applications

  • Applies to patients with recurrent oral ulcers, often seen in adolescents and young adults.
  • Higher prevalence in individuals with a family history of aphthous stomatitis.
  • Clinical settings include outpatient primary care and dental practices.
  • Specialty-specific applications may involve oral medicine and dermatology.
  • Treatment contexts include management of pain and prevention of ulcer recurrence.

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Template 1

Template: 'Patient diagnosed with aphthous stomatitis based on clinical findings of recurrent oral ulcers.'

Template 2

Template: 'Clinical presentation consistent with aphthous stomatitis including painful ulcers on the buccal mucosa.'

Template 3

Template: 'Diagnostic criteria for aphthous stomatitis met as evidenced by multiple ulcers observed during examination.'

Template 4

Template: 'Treatment plan initiated for aphthous stomatitis with topical corticosteroids and pain management.'

Template 5

Template: 'Follow-up care for aphthous stomatitis including monitoring for recurrence and dietary recommendations.'

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What documentation is required for this diagnosis?

Document the presence, size, and location of ulcers, along with any associated symptoms.

How does this differ from similar diagnoses?

Aphthous stomatitis is characterized by non-infectious, recurrent ulcers, unlike herpes simplex which presents with vesicular lesions.

What are common billing considerations?

Ensure that the diagnosis is clearly linked to the treatment provided to optimize reimbursement.

What procedures are typically associated?

CPT codes for treatment may include topical anesthetics or corticosteroids.

Are there any quality reporting implications?

Quality measures may include tracking the frequency of episodes and treatment outcomes.