ICD-10 Code H75.00 – Mastoiditis in Infectious and Parasitic Diseases Classified Elsewhere, Unspecified Ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H75.00 – Mastoiditis in infectious and parasitic diseases classified elsewhere, unspecified ear
What it is
H75.00 identifies mastoiditis affecting the unspecified ear when the underlying infectious or parasitic disease is classified elsewhere. Use it when the mastoid process is involved, but the source condition is coded separately.
Clinical signs
Clinical features may include ear pain, mastoid tenderness, swelling behind the ear, and signs of otitis media. Clinical features vary; refer to documentation.
When to use this code
Use H75.00 when the record documents mastoiditis linked to an infectious or parasitic disease, and the ear is not specified. You should also code the underlying infection or parasitic condition elsewhere in the chart. Check documentation if the note does not clearly state the causal disease or laterality.
Do not use for
Do not use this code for uncomplicated otitis media without mastoid involvement, or for mastoiditis that is not described as secondary to another classified disease. If the ear side is specified, use the appropriate laterality code instead.
Coding tip
Always confirm both the mastoiditis diagnosis and the underlying infection before assigning H75.00.