ICD-10 Code K13.5 – Oral submucous fibrosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K13.5 – Oral submucous fibrosis
What it is
Oral submucous fibrosis is a chronic, progressive disorder of the oral mucosa that causes stiffening and scarring of the mouth lining. It can limit mouth opening and make chewing or speaking difficult.
Clinical signs
Typical findings include blanching or firmness of the oral mucosa, reduced cheek flexibility, and restricted mouth opening. Clinical features vary; refer to documentation.
When to use this code
Use K13.5 when the provider documents oral submucous fibrosis as the confirmed diagnosis or a current active condition. It is appropriate when the record describes fibrosis of the oral mucosa with functional limitation. If the note only says oral pain or mouth ulcer without fibrosis, check documentation.
Do not use for
Do not use this code for general oral inflammation, simple mouth sores, or unspecified oral lesions. If the chart does not clearly document oral submucous fibrosis, check documentation.
Coding tip
Code only when the diagnosis is explicitly stated and supported by exam or specialist documentation.