ICD-10 Code H75.0 – Mastoiditis in infectious and parasitic diseases classified elsewhere (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H75.0 – Mastoiditis in infectious and parasitic diseases classified elsewhere
What it is
H75.0 identifies mastoiditis that is caused by an infectious or parasitic disease classified elsewhere. Use this code when the mastoid inflammation is linked to an underlying condition, not coded here.
Clinical signs
Typical findings include mastoid tenderness, swelling, ear pain, fever, and otorrhea. Clinical features vary; refer to documentation for the specific underlying infection or parasitic disease.
When to use this code
Use H75.0 when the provider documents mastoiditis as secondary to another infectious or parasitic disease and the causal condition is coded elsewhere. This code supports cases where mastoid involvement is part of a broader documented infection. If the record does not clearly link the mastoiditis to another disease, check documentation.
Do not use for
Do not use this code for primary mastoiditis without an underlying infectious or parasitic cause. Also avoid it when the record only documents otitis media, mastoid pain, or an unspecified ear infection.
Coding tip
Always code the underlying infectious or parasitic disease first, and verify the provider’s linkage to mastoiditis.