Mastoiditis in infec/parastc dis classd elswhr, left ear

This code signifies inflammation of the mastoid air cells in the left ear, specifically when it arises as a manifestation of an underlying infectious or parasitic systemic disease. This is a secondary mastoiditis, not a primary infection of the mastoid itself.

Use this code when documentation clearly links left-sided mastoiditis to a systemic infectious or parasitic condition, such as tuberculosis, syphilis, or measles. The medical record must explicitly state the underlying infectious or parasitic disease causing the mastoiditis.

• Always sequence the underlying infectious or parasitic disease code first, followed by this code.
• Ensure the documentation specifies "left ear" and identifies the causative infectious or parasitic agent.
• Do not use for primary mastoiditis or mastoiditis due to local ear infections; those require different codes.