ICD-10-CM 2027 diagnosis code

H70.0Acute mastoiditis

Not billable — use a more specific code

H70.0 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About H70.0

H70.0 is the ICD-10-CM diagnosis code for acute mastoiditis. It belongs to category H70 (mastoiditis and related conditions), block H65-H75 (diseases of middle ear and mastoid) and chapter 8 (diseases of the ear and mastoid process). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within H70 (mastoiditis and related conditions), H70.0 is specifically for acute mastoiditis. Related codes cover chronic mastoiditis (H70.1), petrositis (H70.2), other mastoiditis and related conditions (H70.8) and unspecified mastoiditis (H70.9).

To report this condition, pick the subcode that matches the documentation: H70.00 (without complications), H70.01 (mastoid) and H70.09 (with other complications).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under H70.0

Coding notes

Applicable toConditions and synonyms classified to this code

Abscess of mastoid
Empyema of mastoid

Notes that apply from higher levels

Instructions written at a parent level also apply to H70.0.

Broader instructions also apply from Chapter 8: Diseases of the ear and mastoid process.

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about H70.0

Is H70.0 billable?: No. H70.0 is a header code. Report one of its more specific subcodes instead.