ICD-10 Code for Mastoiditis
Also indexed as (coalescent) (hemorrhagic) (suppurative)
The ICD-10-CM code for mastoiditis is H70.9 — Unspecified mastoiditis. This is the code the Alphabetic Index gives for mastoiditis with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).
H70.9 cannot be submitted on a claim. It is a header code, so a more specific code from the list below is required.
Which mastoiditis code should you use?
The Alphabetic Index lists 10 codes under Mastoiditis. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.
By type
Mastoiditis acute, subacute
Codes under H70.9
Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources