ICD-10 Code B43.9 – Chromomycosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B43.9 – Chromomycosis, unspecified
What it is
B43.9 identifies chromomycosis when the record does not specify the organism or form. It is a chronic fungal infection that usually affects skin and subcutaneous tissue.
Clinical signs
Typical findings include slowly enlarging skin lesions, often verrucous, plaque-like, or nodular. Clinical features vary; refer to documentation, and confirm the diagnosis if the chart supports fungal infection consistent with chromomycosis.
When to use this code
Use this code when the clinician documents chromomycosis but does not name a specific subtype. It also fits nonspecific charting such as “chromomycosis” or “fungal skin infection, chromomycosis,” when no further detail is available.
If the note identifies a specific organism or a different fungal condition, select the more precise code instead. Check documentation for site, extent, and any stated diagnostic confirmation.
Do not use for
Do not use B43.9 for other superficial fungal infections, tinea, or unrelated skin lesions. Do not use it when the record clearly identifies a more specific chromomycosis code.
Coding tip
Review the provider’s wording carefully and code the most specific fungal diagnosis documented.