2026 ICD-10-CM Diagnosis Code H70.099Acute mastoiditis with other complications, unspecified ear

ICD-10-CM Codes›H60–H95›H65-H75›H70

ICD-10-CM H70.099
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H70.099 is a billable ICD-10-CM diagnosis code for acute mastoiditis with other complications, unspecified ear. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 152 through 153. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as acute mastoiditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Diseases of middle ear and mastoid (except otitis media).

Code Identity

ICD-10-CM Code
H70.099
Billable Status
Yes — Valid for Submission
Code Describes
Acute mastoiditis with other complications, unspecified ear
Short Description
Acute mastoiditis with other complications, unspecified ear
Same as the full description in the CMS dataset.
Parent Code
H70.09
Acute mastoiditis with other complications

Code Classification

ChapterH60–H95Diseases of the ear and mastoid process
SectionH65-H75Diseases of middle ear and mastoid
CategoryH70Mastoiditis and related conditions
This CodeH70.099Acute mastoiditis with other complications, unspecified ear

Code EditsBilling

Medicare Code Editor checks that affect claim validity for H70.099.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute mastoiditis
  • Acute mastoiditis with facial paralysis
  • Acute mastoiditis with labyrinthitis
  • Acute mastoiditis with neck abscess
  • Intracranial disorder due to and following acute mastoiditis

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EAR002
Diseases of middle ear and mastoid (except otitis media)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Ear Infections

Ear infections are the most common reason parents bring their child to a doctor. Three out of four children will have at least one ear infection by their third birthday. Adults can also get ear infections, but they are less common.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert H70.099 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
383.02 Ac mastoiditis-compl NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About H70.099Overview

Is H70.099 (Acute mastoiditis with other complications) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report acute mastoiditis with other complications, unspecified ear on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does H70.099 group to?

When acute mastoiditis with other complications, unspecified ear is the principal diagnosis on an inpatient stay, it groups to MS-DRG 152, 153, with relative weights from 0.7382 to 1.1822 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H70.099?

Under the General Equivalence Mappings, acute mastoiditis with other complications, unspecified ear converts to ICD-9-CM 383.02 (ac mastoiditis-compl NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.