ICD-10 Code B36.1 – Tinea nigra (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B36.1 – Tinea nigra
What it is
B36.1 identifies tinea nigra, a superficial fungal infection of the skin. It usually causes a dark, flat patch on the palms or soles and is limited to the outer skin layer.
Clinical signs
Look for a brown to black, non-raised macule with a well-defined border, often on the palm. Clinical features vary; refer to documentation if the lesion description is unclear.
When to use this code
Use this code when the provider documents tinea nigra or a confirmed superficial fungal infection with the classic pigmented skin lesion. It fits outpatient, dermatology, or primary care records when the diagnosis is specific. Check documentation if the chart only notes “dark skin spot” without a fungal diagnosis.
Do not use for
Do not use B36.1 for other causes of skin pigmentation, such as bruising, melanoma, or post-inflammatory hyperpigmentation. If the condition is not documented as tinea nigra, choose a different code or check documentation.
Coding tip
Code B36.1 only when the record supports a fungal diagnosis, not merely the appearance of a pigmented lesion.