ICD-10 Code H70.21 – Acute Petrositis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.21 – Acute petrositis
What it is
H70.21 identifies acute inflammation or infection of the petrous part of the temporal bone. Use it when documentation specifically states acute petrositis.
Clinical signs
Findings may include ear pain, otorrhea, fever, and symptoms related to adjacent ear infection. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents acute petrositis, including cases described as petrous apicitis or acute infection of the petrous bone. It may appear with complicated otitis media or mastoid disease if the record clearly supports petrous involvement. Check documentation when the term is used loosely.
Do not use for
Do not use H70.21 for nonspecific ear infection, mastoiditis without petrous involvement, or chronic petrositis. If the chart does not clearly state acute petrositis, check documentation.
Coding tip
Code H70.21 only when the note names acute petrositis or an equivalent documented diagnosis.