ICD-10 Code B36.9 – Superficial mycosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B36.9 – Superficial mycosis, unspecified
What it is
B36.9 identifies a superficial fungal infection of the skin or its outer layers when the organism or exact type is not specified. Use it for a documented superficial mycosis without a more precise diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Superficial fungal infections commonly present with localized scaling, discoloration, itching, or mild rash limited to the skin surface.
When to use this code
Use B36.9 when the record states superficial mycosis, fungal skin infection, or similar wording but does not identify the specific fungus or site. It also fits when the provider documents a superficial fungal infection and no more specific code is supported. Check documentation if a named condition is recorded.
Do not use for
Do not use this code for deep or systemic fungal infections, or when a more specific superficial fungal diagnosis is documented. If the chart names tinea, candidiasis, or another defined condition, code that diagnosis instead.
Coding tip
Code the most specific fungal diagnosis available; use B36.9 only when the documentation remains nonspecific.