ICD-10 Code K12.30 – Oral mucositis (ulcerative), unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K12.30 – Oral mucositis (ulcerative), unspecified
What it is
K12.30 identifies ulcerative inflammation of the oral mucosa when the site or cause is not further specified. Use it for documented oral mucositis with ulceration and no more precise diagnosis.
Clinical signs
Typical findings include painful sores or ulceration in the mouth, inflamed mucosa, and discomfort with eating or speaking. Clinical features vary; refer to documentation.
When to use this code
Use this code when the record states oral mucositis, ulcerative stomatitis, or similar wording and does not name a more specific condition. It fits cases where the provider documents ulcerative oral mucosal inflammation but does not identify a cause or location. Check documentation if chemotherapy, radiation, infection, or another etiology is recorded.
Do not use for
Do not use K12.30 for non-ulcerative oral inflammation, isolated aphthous ulcers, or oral lesions with a documented specific cause. If a more specific diagnosis is stated, code that condition instead.
Coding tip
Query for cause and specificity before assigning K12.30, because documentation may support a more precise code.