ICD-10 Code H70.019 – Subperiosteal abscess of mastoid, unspecified ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.019 – Subperiosteal abscess of mastoid, unspecified ear
What it is
Use this code for a subperiosteal abscess arising from mastoid infection when the affected ear is not specified. It indicates pus collecting beneath the periosteum over the mastoid bone.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include postauricular swelling, tenderness, erythema, and protrusion of the ear, often with signs of mastoiditis.
When to use this code
Assign H70.019 when the record clearly documents a subperiosteal abscess of the mastoid but does not identify the ear side. Use it for confirmed mastoid-related abscesses, including operative, imaging, or specialist notes that name this diagnosis. If laterality is documented, choose the more specific code.
Do not use for
Do not use this code for simple mastoiditis without abscess formation. Do not use it when the chart identifies the right or left ear and a laterality-specific code is available.
Coding tip
Check documentation for laterality and abscess confirmation before coding H70.019.