Blog
Acanthosis nigricans
Covenant Metabolic Specialists Health Library
Covenant Metabolic Specialists
Physician Reviewed
Dec 3, 2025
What is Acanthosis Nigricans?
Acanthosis nigricans (AN) is a skin disorder where affected areas become darker, thicker, and often feel velvety to the touch. It is not contagious or harmful on its own, but it often signals metabolic dysfunction. The condition is especially common in individuals with obesity or prediabetes and may also appear as a side effect of certain medications or underlying endocrine disorders.
Causes
Acanthosis Nigricans occurs when skin cells reproduce too quickly, often triggered by high insulin levels or hormone imbalances. Common causes include:
Insulin resistance (most common cause)
Type 2 diabetes or prediabetes
Polycystic ovary syndrome (PCOS)
Obesity
Hormonal disorders (thyroid, adrenal glands)
Certain medications (e.g., steroids, birth control pills, high-dose niacin)
Genetic conditions (in rare cases)
Cancer (especially stomach or liver) – this is rare and usually occurs in older adults
Risk Factors
You’re more likely to develop Acanthosis Nigricans if you:
Are overweight or obese
Have a family history of diabetes or insulin resistance
Have darker skin (AN is more common in African American, Latino, and Native American populations)
Have polycystic ovary syndrome (PCOS) or another hormone-related disorder
Use medications that alter hormones or insulin sensitivity
Are dealing with metabolic syndrome
Diagnosis
A diagnosis is typically made through:
Physical Exam: A provider can usually recognize AN by looking at the skin.
Medical History: Your provider may ask about weight changes, medication use, and any underlying health conditions.
Blood Tests: These help determine if diabetes, prediabetes, or a hormonal disorder is contributing.
Biopsy (Rare): In unusual cases, a skin biopsy may be needed to rule out other skin conditions.
Prevention
Acanthosis nigricans isn’t always preventable, but these actions help:
Maintain a healthy weight
Control blood sugar through diet and exercise
Avoid medications known to trigger AN unless necessary
Get regular metabolic health checkups
