ICD-10 Code K12.1 – Other forms of stomatitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K12.1 – Other forms of stomatitis
What it is
K12.1 identifies stomatitis that does not fit a more specific category. It refers to inflammation or irritation of the mouth lining, including oral mucosa, when the cause or type is documented as other forms.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include oral redness, soreness, swelling, or ulceration affecting the mouth mucosa, but you should code only when the record clearly supports stomatitis.
When to use this code
Use K12.1 when the provider documents stomatitis and does not name a more specific diagnosis. It also applies when the chart describes an oral inflammatory condition that is explicitly categorized as “other forms.”
Do not infer this code from vague mouth pain or nonspecific lesions alone. Check documentation for the exact oral diagnosis and code a more specific stomatitis type if one is recorded.
Do not use for
Do not use K12.1 for aphthous ulcers, oral thrush, gingivitis, or traumatic mouth lesions unless the provider specifically documents stomatitis. Check documentation when the condition is better described by another oral diagnosis.
Coding tip
Choose the most specific oral diagnosis available; K12.1 is a fallback only when the record clearly states other forms of stomatitis.