ICD-10 Code H70.90 – Unspecified mastoiditis, unspecified ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.90 – Unspecified mastoiditis, unspecified ear
What it is
H70.90 identifies mastoid inflammation or infection affecting the mastoid region, with no laterality specified. Use it when the record documents mastoiditis but does not state right, left, or a more specific type.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include ear pain, swelling or tenderness behind the ear, fever, and abnormal ear drainage, but you should code only what is documented.
When to use this code
Use H70.90 when the clinician documents mastoiditis and the ear is not identified as right or left. It also fits when the note confirms mastoiditis but does not provide enough detail for a more specific code. Check documentation if the case describes chronic, acute, or postprocedural disease.
Do not use for
Do not use this code for otitis media without mastoid involvement or when a more specific mastoiditis code is documented. If laterality is known, or another type is stated, choose the more precise code.
Coding tip
Query the provider when mastoiditis is mentioned but laterality or specificity is missing.