ICD-10 Code H70.91 – Unspecified mastoiditis, right ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.91 – Unspecified mastoiditis, right ear
What it is
H70.91 identifies mastoid inflammation in the right ear when the record does not specify the exact type. Use it for a documented right-sided mastoiditis diagnosis without further detail.
Clinical signs
Clinical features vary; refer to documentation. Typical mastoiditis may include ear pain, tenderness behind the ear, swelling, redness, or persistent ear infection findings.
When to use this code
Use this code when the provider documents mastoiditis of the right ear but does not name a more specific form. It also fits cases where laterality is clear, yet the subtype remains unspecified. If the note supports a different ear or a more precise diagnosis, code that instead.
Do not use for
Do not use H70.91 if the record identifies left ear, bilateral disease, or a specific mastoiditis type. Check documentation when the diagnosis is only suspected or not confirmed.
Coding tip
Confirm both laterality and specificity in the provider note before assigning H70.91.