Chronic mastoiditis, left ear

This code signifies a persistent, long-standing inflammation of the mastoid air cells located behind the left ear. It typically results from inadequately treated acute otitis media, leading to bone erosion and potential complications such as abscess formation or intracranial spread.

Apply this code when documentation clearly indicates chronic inflammation of the mastoid bone in the left ear. This diagnosis is often supported by imaging studies (e.g., CT scan) showing mastoid opacification, sclerosis, or bone destruction, along with a history of recurrent or persistent ear infections.

• Differentiate from acute mastoiditis (H70.0-) based on the chronicity of the condition.
• Ensure laterality is accurately documented and coded; this code specifically refers to the left ear.
• Look for documentation of associated complications, such as mastoid fistula or subperiosteal abscess, which may require additional coding.