K12.31 Oral mucositis (ulcerative) due to antineoplastic therapy

Billable ICD-10-CM code, FY2026.

Use additional code

• code for adverse effect, if applicable, to identify antineoplastic and immunosuppressive drugs (T45.1X5)
• code for other antineoplastic therapy, such as:
• radiological procedure and radiotherapy (Y84.2)

Applies from K12 Stomatitis and related lesions

Excludes1 (never code together)

• cancrum oris (A69.0)
• cheilitis (K13.0)
• gangrenous stomatitis (A69.0)
• herpesviral [herpes simplex] gingivostomatitis (B00.2)
• noma (A69.0)

Use additional code

• 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)

Applies from K12.3 Oral mucositis (ulcerative)

Applicable to

• Mucositis (oral) (oropharyneal)

Excludes2 (not included here)

• gastrointestinal mucositis (ulcerative) (K92.81)
• mucositis (ulcerative) of vagina and vulva (N76.81)
• nasal mucositis (ulcerative) (J34.81)

MS-DRG index

Defines the logic of DRG(s) 011-013 in MDC PRE.

Approximate ICD-9-CM (GEMs)

• 528.01 Mucositis (ulcerative) due to antineoplastic therapy (approximate)

Code annotations containing back-references to K12.31

Back-references to K12.3

• Code Also: D70 Neutropenia (", if applicable, mucositis (J34.81, K12.3-, K92.81, N76.81)")
• Type 2 Excludes: J34.81 Nasal mucositis (ulcerative) ("oral mucositis (ulcerative) (K12.3-)")
• Type 2 Excludes: K92.81 Gastrointestinal mucositis (ulcerative) ("oral mucositis (ulcerative) (K12.3-)")
• Type 2 Excludes: N76.81 Mucositis (ulcerative) of vagina and vulva ("oral mucositis (ulcerative) (K12.3-)")

Back-references to K12

• Type 2 Excludes: K13 Other diseases of lip and oral mucosa ("stomatitis and related lesions (K12.-)")
• Use Additional: L51 Erythema multiforme ("stomatitis (K12.-)")

Diagnosis Index entries for K12.31

• Mucositis (ulcerative) › mouth (oral) (oropharyngeal) › due to antineoplastic therapy

Nearby codes

• K12.0 Recurrent oral aphthae
• K12.1 Other forms of stomatitis
• K12.2 Cellulitis and abscess of mouth
• K12.3 Oral mucositis (ulcerative)
• K12.30 Oral mucositis (ulcerative), unspecified
• K12.31 Oral mucositis (ulcerative) due to antineoplastic therapy (this code)
• K12.32 Oral mucositis (ulcerative) due to other drugs
• K12.33 Oral mucositis (ulcerative) due to radiation
• K12.39 Other oral mucositis (ulcerative)