Skip to content
Dx

ICD-10-CM 2027 diagnosis code

K12Stomatitis and related lesions

Not billable — use a more specific code

K12 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About K12

K12 is the ICD-10-CM diagnosis code for stomatitis and related lesions. It belongs to block K00-K14 (diseases of oral cavity and salivary glands) and chapter 11 (diseases of the digestive system). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: K12.0 (aphthae), K12.1 (stomatitis), K12.2 (mouth) and K12.3 ((ulcerative)).

Don't report K12 together with the conditions in its Excludes1 note: cancrum oris (A69.0), cheilitis (K13.0), gangrenous stomatitis (A69.0), herpesviral [herpes simplex] gingivostomatitis (B00.2) and 1 more.

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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under K12

Coding notes

Excludes1Not coded here — never report together with this code
  • cancrum oris (A69.0)
  • cheilitis (K13.0)
  • gangrenous stomatitis (A69.0)
  • herpesviral [herpes simplex] gingivostomatitis (B00.2)
  • noma (A69.0)
Use additional codeAdd a secondary code to fully describe the condition
  • 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)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Notes that apply from higher levels

Instructions written at a parent level also apply to K12.

Broader instructions also apply from Chapter 11: Diseases of the digestive system.

Codes whose notes reference K12

  • K13Excludes2
  • L51Use additional code

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about K12

Is K12 billable?

No. K12 is a header code. Report one of its more specific subcodes instead.