ICD-10 Code H70.13 – Chronic mastoiditis, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H70.13 – Chronic mastoiditis, bilateral
What it is
H70.13 identifies chronic inflammation or infection of the mastoid air cells in both ears. Use it when the record clearly documents bilateral chronic mastoiditis.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include persistent ear drainage, hearing loss, and mastoid tenderness or swelling, but the diagnosis should be supported by the clinician’s assessment.
When to use this code
Use H70.13 when the provider documents chronic mastoiditis affecting both mastoids, whether active or longstanding. Apply it from office notes, ENT consults, or imaging-supported assessments that clearly state the bilateral condition.
Check documentation if the chart only mentions mastoid pain, otitis media, or a history of ear disease without confirming chronic bilateral mastoiditis. Code the documented condition that is actually established.
Do not use for
Do not use this code for acute mastoiditis, unilateral mastoiditis, or nonspecific ear infection. If laterality or chronicity is not stated, check documentation.
Coding tip
Confirm both chronicity and bilateral laterality in the provider record before assigning H70.13.