ICD-10-CM 2027
ICD-10 code for mycosis
From the official ICD-10-CM alphabetic index entry “Mycosis, mycotic”. Page updated September 29, 2026.
About coding mycosis
The ICD-10-CM code for mycosis is B49 (Unspecified mycosis). The official index lists 14 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on B49.
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 867 (Other Infectious and Parasitic Diseases Diagnoses with MCC, relative weight 2.1859), DRG 868 (Other Infectious and Parasitic Diseases Diagnoses with CC, relative weight 1.0235) and DRG 869 (Other Infectious and Parasitic Diseases Diagnoses without CC/MCC, relative weight 0.6787), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
More specific mycosis codes (official index)
- cutaneous NEC B36.9 — Superficial mycosis, unspecified
- ear B36.9 — Superficial mycosis, unspecified
- in
- aspergillosis B44.89 — Other forms of aspergillosis
- candidiasis B37.84 — Candidal otitis externa
- moniliasis B37.84 — Candidal otitis externa
- fungoides (extranodal) (solid organ) C84.0 — Mycosis fungoides
- mouth B37.0 — Candidal stomatitis
- nails B35.1 — Tinea unguium
- opportunistic B48.8 — Other specified mycoses
- skin NEC B36.9 — Superficial mycosis, unspecified
- specified NEC B48.8 — Other specified mycoses
- stomatitis B37.0 — Candidal stomatitis
- vagina, vaginitis (candidal) (acute) B37.31 — Acute candidiasis of vulva and vagina
- chronic (recurrent) B37.32 — Chronic candidiasis of vulva and vagina
Common questions about mycosis ICD-10 codes
What is the ICD-10 code for mycosis?
- B49 — Unspecified mycosis. More specific codes apply when the documentation supports them: B36.9, B36.9, B44.89, B37.84 and others below.
What is the ICD-10 code for cutaneous nec mycosis?
- B36.9 — Superficial mycosis, unspecified.
What is the ICD-10 code for ear mycosis?
- B36.9 — Superficial mycosis, unspecified.
What is the ICD-10 code for fungoides mycosis?
- C84.0 — Mycosis fungoides (header code; choose a more specific subcode).
What is the ICD-10 code for mouth mycosis?
- B37.0 — Candidal stomatitis.
What is the ICD-10 code for nails mycosis?
- B35.1 — Tinea unguium.
What is the ICD-10 code for opportunistic mycosis?
- B48.8 — Other specified mycoses.
Is B49 billable?
- Yes. B49 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B49 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B49 as a principal diagnosis.
Is B49 a CC or MCC?
- B49 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.