ICD-10-CM 2027
ICD-10 code for Aphthous stomatitis
From the official ICD-10-CM alphabetic index entry “Stomatitis (denture) (ulcerative) › aphthous”. Page updated September 29, 2026.
About coding Aphthous stomatitis
The ICD-10-CM code for Aphthous stomatitis is K12.0 (Recurrent oral aphthae).
Within K12 (stomatitis and related lesions), K12.0 is specifically for recurrent oral aphthae. Related codes cover other forms of stomatitis (K12.1), cellulitis and abscess of mouth (K12.2) and oral mucositis (ulcerative) (K12.3).
Use an additional code to identify: alcohol abuse and dependence (F10.-), exposure to environmental tobacco smoke (Z77.22), exposure to tobacco smoke in the perinatal period (P96.81), history of tobacco dependence (Z87.891), occupational exposure to environmental tobacco smoke (Z57.31) and 2 more.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Common questions about Aphthous stomatitis ICD-10 codes
What is the ICD-10 code for Aphthous stomatitis?
- K12.0 — Recurrent oral aphthae.
Is K12.0 billable?
- Yes. K12.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K12.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K12.0 as a principal diagnosis.
Is K12.0 a CC or MCC?
- No. K12.0 is neither a CC nor an MCC under MS-DRG v44.0.