ICD-10 Code H70.002 – Acute mastoiditis without complications, left ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.002 – Acute mastoiditis without complications, left ear
What it is
H70.002 identifies an acute infection and inflammation of the mastoid air cells in the left ear, without documented complications. Use it when the provider specifies left-sided acute mastoiditis and does not report extension or other complicating features.
Clinical signs
Common findings include ear pain, fever, swelling or tenderness behind the ear, and a protruding auricle. Clinical features vary; refer to documentation for the laterality and whether the mastoid process is involved without complications.
When to use this code
Use this code when the record clearly states acute mastoiditis affecting the left ear and there is no mention of abscess, intracranial spread, or other complications. It also fits when imaging or specialist notes confirm mastoid inflammation on the left side. Check documentation if laterality is unclear.
Do not use for
Do not use H70.002 for chronic mastoiditis, unspecified mastoiditis, or acute mastoiditis with complications. If the note does not specify the left ear, check documentation before assigning this code.
Coding tip
Confirm both acute status and left-ear laterality in the provider note before coding.