2027 ICD-10-CM Diagnosis Code B43.1Pheomycotic brain abscess

ICD-10-CM Codes›A00–B99›B35-B49›B43

ICD-10-CM B43.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

B43.1 is a billable ICD-10-CM diagnosis code for pheomycotic brain abscess. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 867 through 869. Coders also document this condition as infection by Cladosporium trichoides. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under CNS abscess and Fungal infections.

Code Identity

ICD-10-CM Code
B43.1
Billable Status
Yes — Valid for Submission
Code Describes
Pheomycotic brain abscess
Short Description
Pheomycotic brain abscess
Same as the full description in the CMS dataset.
Parent Code
B43
Chromomycosis and pheomycotic abscess

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB35-B49Mycoses
CategoryB43Chromomycosis and pheomycotic abscess
This CodeB43.1Pheomycotic brain abscess

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Infection by Cladosporium trichoides
  • Infection of brain caused by Form Dematiaceae
  • Phaeohyphomycosis
  • Pheohyphomycotic brain abscess

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to B43.1: its own notes plus those printed at block B35-B49 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Cerebral chromomycosis

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block B35-B49 Mycoses applies to 104 codes
  • hypersensitivity pneumonitis due to organic dust (J67.-)
  • mycosis fungoides (C84.0-)
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name B43.1, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming B43.1: they are not reported together with it, unless the two conditions are unrelated.

  • G07 Intracranial and intraspinal abscess and granuloma in diseases classified elsewhere
    chromomycotic (B43.1)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR NVS014
CNS abscess
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF004
Fungal infections
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Abscess

An abscess is a pocket of pus. You can get an abscess almost anywhere in your body. When an area of your body becomes infected, your body's immune system tries to fight the infection. White blood cells go to the infected area, collect within the damaged tissue, and cause inflammation. During this process, pus forms.

Read the full article at MedlinePlus

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

Convert B43.1 to ICD-9-CMHistory

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

ICD-9-CM
117.2 Chromoblastomycosis
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About B43.1Overview

What is the ICD-10 code for pheomycotic brain abscess?

The ICD-10-CM code for pheomycotic brain abscess is B43.1 (sometimes written as B431). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is B43.1 (Chromomycosis and pheomycotic abscess) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pheomycotic brain abscess on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does B43.1 group to?

When pheomycotic brain abscess is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 869, 868, with relative weights from 0.6784 to 2.1855 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B43.1?

Under the General Equivalence Mappings, pheomycotic brain abscess converts to ICD-9-CM 117.2 (chromoblastomycosis). The mapping is approximate, so confirm the match fits the documentation.