ICD-10 Code H70.001 – Acute mastoiditis without complications, right ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.001 – Acute mastoiditis without complications, right ear
What it is
H70.001 identifies acute mastoiditis affecting the right ear without documented complications. It means the mastoid air cells behind the ear are acutely infected or inflamed, and you should code the right-sided location exactly as documented.
Clinical signs
Typical findings include ear pain, fever, swelling or tenderness behind the ear, and a protruding auricle. Clinical features vary; refer to documentation, and confirm that the record supports acute mastoiditis rather than another ear infection.
When to use this code
Use this code when the provider documents acute mastoiditis in the right ear and does not describe complications such as abscess, meningitis, or bone involvement beyond the uncomplicated infection. It is also appropriate when imaging or exam findings support the diagnosis and the right side is specified.
Do not use for
Do not use H70.001 for mastoiditis with complications or when the side is not right. If the chart only says otitis media, ear pain, or suspected mastoiditis, check documentation before coding.
Coding tip
Always verify laterality and whether the provider explicitly states “without complications” before assigning H70.001.