ICD-10 Code H70.00 – Acute mastoiditis without complications (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.00 – Acute mastoiditis without complications
What it is
H70.00 identifies acute infection and inflammation of the mastoid air cells without documented complications. Use it when the record shows mastoiditis, but no abscess, intracranial spread, or other complication is noted.
Clinical signs
Typical findings include ear pain, tenderness or swelling behind the ear, fever, and otitis media-related symptoms. Clinical features vary; refer to documentation.
When to use this code
Use H70.00 when the provider documents acute mastoiditis and specifically states it is uncomplicated. It also fits cases where imaging or examination confirms mastoid involvement, but the chart does not describe a complication. If the note mentions extension beyond the mastoid, check documentation for a more specific code.
Do not use for
Do not use this code for mastoiditis with abscess, intracranial complications, or chronic mastoid disease. Check documentation if the record is vague about acuity or complication status.
Coding tip
Always verify that “without complications” is supported in the provider note before assigning H70.00.