2026 ICD-10-CM Diagnosis Code K13.1Cheek and lip biting

ICD-10-CM Codes›K00–K95›K00-K14›K13

ICD-10-CM K13.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K13.1 is a billable ICD-10-CM diagnosis code for cheek and lip biting. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 157 through 159. Coders also document this condition as biting of oral mucosa. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Diseases of mouth; excluding dental, and Nontraumatic dental conditions.

Code Identity

ICD-10-CM Code
K13.1
Billable Status
Yes — Valid for Submission
Code Describes
Cheek and lip biting
Short Description
Cheek and lip biting
Same as the full description in the CMS dataset.
Parent Code
K13
Other diseases of lip and oral mucosa

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK13Other diseases of lip and oral mucosa
This CodeK13.1Cheek and lip biting

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Biting of oral mucosa
  • Cheek biting
  • Lip biting

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Biting, cheek or lip

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DEN001
Any dental condition including traumatic injury
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG003
Diseases of mouth; excluding dental
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Mouth Disorders

Your mouth is one of the most important parts of your body. It has many different functions. It allows you to:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K13.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
528.9 Oral soft tissue dis NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K13.1Overview

Is K13.1 (Other diseases of lip and oral mucosa) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cheek and lip biting on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K13.1 group to?

When cheek and lip biting is the principal diagnosis on an inpatient stay, it groups to MS-DRG 157, 158, 159, with relative weights from 0.7085 to 1.7168 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K13.1?

Under the General Equivalence Mappings, cheek and lip biting converts to ICD-9-CM 528.9 (oral soft tissue dis NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.