ICD-10 Code H70.899 – Other mastoiditis and related conditions, unspecified ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.899 – Other mastoiditis and related conditions, unspecified ear
What it is
This code identifies mastoiditis or a related mastoid condition when the ear is not specified. Use it when the documentation confirms mastoid involvement but does not name the side.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include mastoid pain, swelling, tenderness, or ear drainage, along with evidence of inflammation involving the mastoid area.
When to use this code
Use this code when the provider documents other mastoiditis or a related mastoid condition and does not identify right or left ear. It also fits cases where the note clearly supports mastoid disease but remains nonspecific about laterality. Check documentation if the diagnosis is uncertain.
Do not use for
Do not use this code if the record specifies the right or left ear, or if a different mastoid disorder is documented. Do not assign it when mastoiditis is not supported by the provider note.
Coding tip
Before assigning H70.899, confirm that laterality is truly unavailable in the documentation.