2026 ICD-10-CM Diagnosis Code K05.221Aggressive periodontitis, generalized, slight

ICD-10-CM Codes›K00–K95›K00-K14›K05

ICD-10-CM K05.221
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K05.221 is a billable ICD-10-CM diagnosis code for aggressive periodontitis, generalized, slight. 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 acute periodontitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury; Caries, periodontitis, and other preventable dental conditions; and Disorders of teeth and gingiva.

Code Identity

ICD-10-CM Code
K05.221
Billable Status
Yes — Valid for Submission
Code Describes
Aggressive periodontitis, generalized, slight
Short Description
Aggressive periodontitis, generalized, slight
Same as the full description in the CMS dataset.
Parent Code
K05.22
Aggressive periodontitis, generalized

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK05Gingivitis and periodontal diseases
This CodeK05.221Aggressive periodontitis, generalized, slight

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute periodontitis
  • Generalized slight aggressive periodontitis

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.

    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • gingival
        • aggressive
          • generalized
            • slight
    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • gum
        • aggressive
          • generalized
            • slight
    • Periodontitis(chronic) (complex) (compound) (local) (simplex)
      • acute
        • generalized
          • slight
    • Periodontitis(chronic) (complex) (compound) (local) (simplex)
      • aggressive
        • generalized
          • slight

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 DEN003
Caries, periodontitis, and other preventable dental conditions
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG002
Disorders of teeth and gingiva
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Acute Periodontitis

    an acute inflammatory process that affects the tissues that surround and support the teeth.

Patient EducationClinical

Gum Disease

If you have gum disease, you're not alone. Many U.S. adults currently have some form of the disease. It ranges from simple gum inflammation, called gingivitis, to serious damage to the tissue and bone supporting the teeth. In the worst cases, you can lose teeth.

Read the full article at MedlinePlus

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

Convert K05.221 to ICD-9-CMHistory

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

ICD-9-CM
523.32 Aggres periodontitis,gen
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement K05.221 replaces the following previously assigned code(s):

  • K05.22 - Aggressive periodontitis, generalized
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K05.221Overview

Is K05.221 (Aggressive periodontitis, generalized) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report aggressive periodontitis, generalized, slight on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K05.221 group to?

When aggressive periodontitis, generalized, slight 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 K05.221?

Under the General Equivalence Mappings, aggressive periodontitis, generalized, slight converts to ICD-9-CM 523.32 (aggres periodontitis,gen). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.