ICD-10 Code H70 – Mastoiditis and related conditions (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70 – Mastoiditis and related conditions
What it is
H70 identifies mastoiditis and other inflammatory conditions involving the mastoid process, usually as complications of ear infection. Use it when the record documents mastoid involvement, not just routine otitis media.
Clinical signs
Typical findings include ear pain, swelling or tenderness behind the ear, fever, and signs of middle ear infection. Clinical features vary; refer to documentation.
When to use this code
Use H70 when the provider documents mastoiditis, mastoid abscess, or another related mastoid inflammatory disorder. It may also apply when imaging or examination confirms mastoid involvement linked to an ear infection. Code only when the condition is specifically documented.
Do not use for
Do not use H70 for uncomplicated otitis media without mastoid involvement. If the chart does not clearly identify mastoid disease, check documentation.
Coding tip
Verify whether the note specifies mastoiditis, a related mastoid condition, or only ear infection before assigning H70.