ICD-10 Code K05.21 – Aggressive Periodontitis, Localized (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K05.21 – Aggressive periodontitis, localized
What it is
K05.21 identifies localized aggressive periodontitis, a rapidly progressing periodontal disease affecting specific teeth rather than the entire mouth. Use this code when the record clearly documents the localized form.
Clinical signs
Typical findings include rapid attachment loss and bone destruction around selected teeth, often with deep periodontal pockets and minimal plaque compared with the severity. Clinical features vary; refer to documentation.
When to use this code
Use K05.21 when the clinician documents aggressive periodontitis limited to a localized pattern, usually involving a small group of teeth. It is appropriate when the diagnosis is explicit and the record supports localized disease rather than generalized periodontal involvement. Check documentation if the extent is unclear.
Do not use for
Do not use this code for generalized aggressive periodontitis or for unspecified periodontal disease. If the note only says periodontitis without the aggressive localized pattern, choose the more accurate documented diagnosis.
Coding tip
Confirm that “localized” and “aggressive periodontitis” both appear in the documentation before assigning K05.21.