The evaluation of acanthosis nigricans begins with a medical history and physical examination.

The diagnosis of acanthosis nigricans is usually made during physical examination.

Sometimes a skin biopsy is performed to confirm the diagnosis. The presence of this acanthosis nigricans may require a detailed evaluation to exclude underlying skin cancer.

Tests for acanthosis nigricans may include:

• Skin biopsy
• Glucose tolerance testing
• Glycosylated hemoglobin level