Postauricular fistula, left ear

This code describes an abnormal, persistent tract or opening located behind the left ear, which typically connects to the mastoid bone or middle ear space. This fistula may drain fluid, pus, or debris, indicating an underlying inflammatory or infectious process. It often results from a complication of mastoiditis or otitis media, or less commonly, from a congenital anomaly.

Use this code when documentation clearly specifies a postauricular fistula affecting the left ear. This diagnosis is supported by findings such as a draining sinus tract behind the auricle, imaging studies confirming a connection to the mastoid, or a history of recurrent infection in that area. It is appropriate for both initial diagnosis and ongoing management of this condition.

• Ensure laterality is explicitly documented as "left ear" to support this specific code.
• Distinguish from preauricular fistulas (Q18.1), which are typically congenital and located in front of the ear.
• Code any associated infections (e.g., mastoiditis, cellulitis) separately, following sequencing guidelines.