2026 ICD-10-CM Diagnosis Code B49Unspecified mycosis

ICD-10-CM Codes›A00–B99›B35-B49›B49

ICD-10-CM B49
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B49 is a billable ICD-10-CM diagnosis code for unspecified mycosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Fungal infections.

Code Identity

ICD-10-CM Code
B49
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified mycosis
Chapter
B35-B49
Mycoses

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB35-B49Mycoses
CategoryB49Unspecified mycosis
This CodeB49Unspecified mycosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of intracranial subdural space caused by fungus
  • Abscess of spinal cord caused by fungus
  • Abscess of subdural space caused by fungus
  • Abscess of subdural space of spinal cord caused by fungus
  • Acute fungal thyroiditis
  • Acute fungal tubulointerstitial nephritis
  • Acute infectious tubulointerstitial nephritis
  • Acute pyelonephritis
  • Acute sinusitis caused by fungus
  • Acute thyroiditis
  • Acute tubulointerstitial nephritis
  • Allergic bronchopulmonary mycosis
  • Allergic fungal sinusitis
  • Arthropathy associated with a mycosis
  • Arthropathy associated with mycoses, of multiple sites
  • Arthropathy associated with mycoses, of the ankle and/or foot
  • Arthropathy associated with mycoses, of the hand
  • Arthropathy associated with mycoses, of the pelvic region and thigh
  • Arthropathy associated with mycoses, of the shoulder region
  • Bilateral fungal keratitis
  • Bronchomoniliasis
  • Candida sake or Candida famata or Yarrowia lipolytica
  • Cardiovascular abnormality due to infective myocarditis
  • Chorioamnionitis
  • Chorioamnionitis caused by fungus
  • Chronic catarrhal rhinitis
  • Dilated cardiomyopathy due to fungal myocarditis
  • Dilated cardiomyopathy due to infectious disease
  • Duodenal ulcer caused by fungus
  • Early neonatal infection caused by fungus
  • Endogenous endophthalmitis
  • Endogenous fungal endophthalmitis
  • Enthesitis
  • Erythema multiforme due to systemic fungal infection
  • Erythema nodosum due to systemic fungal infection
  • Exogenous fungal endophthalmitis
  • Fungal arthritis
  • Fungal cardiovascular infection
  • Fungal chorioretinitis
  • Fungal choroiditis
  • Fungal colitis
  • Fungal conjunctivitis
  • Fungal duodenitis
  • Fungal ear infection
  • Fungal encephalitis
  • Fungal endophthalmitis
  • Fungal esophagitis
  • Fungal gastroenteritis
  • Fungal gastrointestinal infection
  • Fungal granuloma
  • Fungal hydrocephalus
  • Fungal infection associated with peritoneal dialysis catheter
  • Fungal infection of bile duct
  • Fungal infection of brain
  • Fungal infection of central nervous system
  • Fungal infection of cerebrum
  • Fungal infection of cranial nerve
  • Fungal infection of eye
  • Fungal infection of kidney
  • Fungal infection of liver
  • Fungal infection of lung
  • Fungal keratitis
  • Fungal meningitis
  • Fungal musculoskeletal infection
  • Fungal myocarditis
  • Fungal myositis
  • Fungal neuritis
  • Fungal panuveitis
  • Fungal peritonitis
  • Fungal pneumonia
  • Fungal respiratory infection
  • Fungal sinusitis
  • Fungal spinal cord compression
  • Fungal spinal epidural abscess
  • Fungal tenosynovitis
  • Fungal ventriculitis
  • Fungemia
  • Fungus isolated but not further identified
  • Gastric ulcer caused by fungus
  • Gastritis caused by fungus
  • Gingival erythema
  • Granuloma of intracranial structure caused by fungus
  • Granuloma of spinal cord caused by fungus
  • Granuloma of spinal epidural space caused by fungus
  • Infection associated with peritoneal dialysis catheter
  • Infection caused by antimicrobial resistant fungi
  • Infection causing granuloma of extradural space of spinal cord
  • Infection causing granuloma of spinal cord
  • Infection causing spondyloarthritis
  • Infection of lacrimal gland caused by fungus
  • Infection of peripheral nerve caused by fungus
  • Infection of upper respiratory tract caused by fungus
  • Infectious panuveitis
  • Infectious thyroiditis
  • Infective ventriculitis
  • Inflammation of bursa caused by fungus
  • Inflammation of intervertebral disc caused by fungus
  • Invasive fungal infection
  • Invasive fungal sinusitis
  • Keratitis of left eye caused by fungus
  • Keratitis of right eye caused by fungus
  • Linear gingival erythema
  • Linear gingival erythema caused by fungus
  • Mold isolated but not further identified
  • Mycosis
  • Mycosis due to human immunodeficiency virus infection
  • Mycotic pericarditis
  • Myelitis caused by fungus
  • Neonatal fungal infection of skin
  • Opportunistic infectious disease
  • Opportunistic mycosis
  • Opportunistic mycosis co-occurrent with human immunodeficiency virus infection
  • Oral mucosal fungal disease
  • Pichia kudriavzevii or Candida inconspicua
  • Pichia kudriavzevii or Candida inconspicua or Candida lambica
  • Pneumonia in systemic mycosis
  • Rhinitis caseosa
  • Sepsis caused by fungus
  • Spinal epidural abscess
  • Spinal subdural abscess
  • Spinal subdural granuloma caused by fungus
  • Spondyloarthritis caused by fungus
  • Subdural abscess
  • Subdural intracranial abscess
  • Suppurative arthritis caused by fungus
  • Systemic mycosis
  • Thyroid infection
  • Unidentified isolate
  • Ventriculitis of the brain
  • Yeast isolated but not further identified

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Fungemia NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)
      • in (due to)
        • mycosis NEC
    • Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)
      • mycotic NEC
    • Bronchomycosis NOS
    • Cough(affected) (epidemic) (nervous)
      • tea taster's
    • Diarrhea, diarrheal(disease) (infantile) (inflammatory)
      • mycotic NEC
    • Disease, diseased
      • fungus NEC
    • Disease, diseased
      • mycotic
    • Fungemia NOS
    • Fungus, fungous
      • disease NOS
    • Infection, infected, infective(opportunistic)
      • fungus NOS
    • Infection, infected, infective(opportunistic)
      • mycelium NOS
    • Infection, infected, infective(opportunistic)
      • mycotic NOS
    • Keratomycosis
    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • mycotic NEC
    • Mycelium infection
    • Mycosis, mycotic
    • Myositis
      • in (due to)
        • mycosis
    • Myositis
      • mycotic
    • Pneumomycosis

Clinical ClassificationClinical

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

CCSR INF004
Fungal infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Chorioamnionitis

    inflammation of the placental membranes (chorion; amnion) and connected tissues such as fetal blood vessels and umbilical cord. it is often associated with intrauterine ascending infections during pregnancy.

  • Allergic Fungal Sinusitis

    fungal infection in the paranasal sinuses characterized by common allergy respiratory symptoms, recurrent nasal polyps and/or asthma with buildup of allergic mucin.

  • Fungemia

    the presence of fungi circulating in the blood. opportunistic fungal sepsis is seen most often in immunosuppressed patients with severe neutropenia or in postoperative patients with intravenous catheters and usually follows prolonged antibiotic therapy.

  • Enthesitis

    inflammation at the site of insertion of ligaments, tendons, and other fibrous structures into bone.

  • Enthesitis-Related Arthritis|ERA|ERA|Enthesitis-Related JIA|Enthesitis-Related JIA|Enthesitis-Related Juvenile Idiopathic Arthritis|Enthesitis-Related Juvenile Idiopathic Arthritis

    a category of juvenile idiopathic arthritis associated with arthritis and enthesitis, which may involve the axial skeleton. it is a form of juvenile spondyloarthritis.

  • Fungal Esophagitis

    infection of the esophagus caused by fungi, most often candida albicans and candida tropicalis. it usually affects patients with immunodeficiency disorders or diabetes mellitus. symptoms include dysphagia and pain on swallowing.

  • Fungal Keratitis

    keratitis caused by fungi.

  • Acute Pyelonephritis

    sudden onset pyelonephritis.

  • Fungal Endophthalmitis

    inflammation of the lining of the ocular cavities, which results from a fungal infection.

  • Fungemia

    a laboratory test result indicating the presence of fungi or yeasts in the blood.

  • Fungemia, CTCAE|Fungemia

    a disorder characterized by the presence of fungus in the blood stream.

  • Grade 2 Fungemia, CTCAE|Grade 2 Fungemia

    moderate symptoms; medical intervention indicated

  • Grade 3 Fungemia, CTCAE|Grade 3 Fungemia

    severe or medically significant but not immediately life-threatening; hospitalization or prolongation of existing hospitalization indicated

  • Chorioamnionitis

    a morphologic finding indicating inflammation of the fetal sac membranes. it is characterized by neutrophilic infiltration of the amnion and chorion.

  • Clinical Chorioamnionitis

    inflammation of the fetal sac membranes, characterized by otherwise unexplained fever (at or above 38 degree c (100.4f)) with one or more of the following: uterine tenderness and/or irritability, leukocytosis, fetal tachycardia, maternal tachycardia, or malodorous vaginal discharge.

  • Histologic Chorioamnionitis|Acute Amnionitis|Acute Chorioamnionitis|Acute Choriodeciduitis|Acute Chorionitis|Microscopic Chorioamnionitis

    inflammation of the fetal sac membranes that is characterized by neutrophilic infiltration of the amnion and chorion.

Patient EducationClinical

Fungal Infections

If you have ever had athlete's foot or a yeast infection, you can blame a fungus. A fungus is a primitive organism. Mushrooms, mold and mildew are examples. Fungi live in air, in soil, on plants and in water. Some live in the human body. Only about half of all types of fungi are harmful.

Read the full article at MedlinePlus

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

Convert B49 to ICD-9-CMHistory

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

ICD-9-CM
117.9 Mycoses NEC & NOS
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 B49Overview

Is B49 (Unspecified mycosis) a billable code?

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

What MS-DRG does B49 group to?

When unspecified mycosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B49?

Under the General Equivalence Mappings, unspecified mycosis converts to ICD-9-CM 117.9 (mycoses NEC & NOS). 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.