ICD-10 Code H70.011 – Subperiosteal Abscess of Mastoid, Right Ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.011 – Subperiosteal abscess of mastoid, right ear
What it is
This code identifies a subperiosteal abscess forming over the mastoid bone on the right side. It usually reflects a complication of mastoid infection, with pus collecting beneath the periosteum.
Clinical signs
Typical findings include postauricular swelling, tenderness, erythema, and ear displacement on the affected side. Clinical features vary; refer to documentation.
When to use this code
Use H70.011 when documentation states a right-sided subperiosteal abscess of the mastoid, or a mastoid abscess with clear right-ear laterality. You may also use it when the provider links the abscess to mastoid disease and specifies the right ear.
Do not use for
Do not use this code for uncomplicated mastoiditis without abscess, or for nonspecific ear infection. If the record does not specify right-sided involvement, check documentation.
Coding tip
Always confirm laterality and the word “subperiosteal abscess” in the provider note before assigning H70.011.