ICD-10-CM > H60-H95 > H65-H75 > H70 > H70.1 H70.1 Chronic mastoiditis Non-Billable/Non-Specific Applicable To Caries of mastoidFistula of mastoid Type 1 Excludes tuberculous mastoiditis (A18.03) Codes H70.10Chronic mastoiditis, unspecified earH70.11Chronic mastoiditis, right earH70.12Chronic mastoiditis, left earH70.13Chronic mastoiditis, bilateral