2026 ICD-10-CM Diagnosis Code K05.20Aggressive periodontitis, unspecified

ICD-10-CM Codes›K00–K95›K00-K14›K05

ICD-10-CM K05.20
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K05.20 is a billable ICD-10-CM diagnosis code for aggressive periodontitis, unspecified. 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. 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
K05.20
Billable Status
Yes — Valid for Submission
Code Describes
Aggressive periodontitis, unspecified
Short Description
Aggressive periodontitis, unspecified
Same as the full description in the CMS dataset.
Parent Code
K05.2
Aggressive periodontitis

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK05Gingivitis and periodontal diseases
This CodeK05.20Aggressive periodontitis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of oral soft tissue
  • Acute gingivitis
  • Acute multiple gingival abscesses
  • Acute necrotizing ulcerative periodontitis
  • Acute pericoronitis
  • Acute periodontitis
  • Aggressive periodontitis
  • Injury of periodontal tissue
  • Multiple abscesses
  • Necrotizing periodontal disease
  • Necrotizing ulcerative periodontitis
  • Pericoronitis

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
    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • gum
        • aggressive
    • Infection, infected, infective(opportunistic)
      • peridental, periodontal
    • Infection, infected, infective(opportunistic)
      • tooth, teeth
        • peridental, periodontal
    • Pericementitis(chronic) (suppurative)
      • acute
    • Periodontitis(chronic) (complex) (compound) (local) (simplex)
      • acute
    • Periodontitis(chronic) (complex) (compound) (local) (simplex)
      • aggressive
    • Suppuration, suppurative
      • gum

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

  • Aggressive Periodontitis

    inflammation and loss of periodontium that is characterized by rapid attachment loss and bone destruction in the presence of little local factors such as dental plaque and dental calculus. this highly destructive form of periodontitis often occurs in young people and was called early-onset periodontitis, but this disease also appears in old people.

  • Pericoronitis

    inflammation of the gingiva surrounding the crown of a tooth.

  • 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 K05.20 to ICD-9-CMHistory

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

ICD-9-CM
523.30 Aggres periodontitis NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
523.33 Acute periodontitis
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 K05.20Overview

Is K05.20 (Aggressive periodontitis) a billable code?

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

What MS-DRG does K05.20 group to?

When aggressive periodontitis, unspecified 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 K05.20?

Under the General Equivalence Mappings, aggressive periodontitis, unspecified converts to ICD-9-CM 523.30 (aggres periodontitis NOS) and 523.33 (acute periodontitis). 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.