K12.0 Recurrent oral aphthae

Billable ICD-10-CM code, FY2026.

Applicable to

• Aphthous stomatitis (major) (minor)
• Bednar's aphthae
• Periadenitis mucosa necrotica recurrens
• Recurrent aphthous ulcer
• Stomatitis herpetiformis

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)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 528.2 Oral aphthae

Code annotations containing back-references to K12.0

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 K12.0

• Aphthae, aphthous › Bednar's
• Aphthae, aphthous › oral (recurrent)
• Aphthae, aphthous › stomatitis (major) (minor)
• Aphthae, aphthous › ulcer (oral) (recurrent)
• Bednar's › aphthae
• Canker (mouth) (sore)
• Periadenitis mucosa necrotica recurrens
• Sore › mouth › canker
• Stomatitis (denture) (ulcerative) › aphthous
• Stomatitis (denture) (ulcerative) › herpetiformis
• Ulcer, ulcerated, ulcerating, ulceration, ulcerative › aphthous (oral) (recurrent)

Nearby codes

• K12 Stomatitis and related lesions
• K12.0 Recurrent oral aphthae (this code)
• 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