ICD-10 Code H70.099 – Acute mastoiditis with other complications, unspecified ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.099 – Acute mastoiditis with other complications, unspecified ear
What it is
H70.099 identifies acute mastoiditis involving the mastoid air cells, with complications other than the usual ones, and the ear is not specified. Use it when the record documents acute mastoid inflammation plus an additional complication.
Clinical signs
Typical findings include ear pain, swelling or tenderness behind the ear, fever, and otitis media history. Clinical features vary; refer to documentation, especially for any stated complication or laterality.
When to use this code
Use this code when the provider clearly documents acute mastoiditis with other complications and does not identify the affected ear. It fits inpatient, emergency, or specialty notes that describe mastoid infection with extension or another complication. If the complication is not stated, check documentation.
Do not use for
Do not use it for uncomplicated mastoiditis, chronic mastoid disease, or cases where a different specific complication is documented. Also avoid it when the ear side is known and a more specific code is available.
Coding tip
Confirm both the acute mastoiditis diagnosis and the documented complication before assigning H70.099.