Dark Underarms and Neck: Acanthosis Nigricans Explained
Dark, velvety skin on the neck or underarms is often acanthosis nigricans, linked to insulin resistance. Learn causes, tests and treatments that actually help.
Condition guide
Acanthosis nigricans
Also known as Dark underarms, Dark neck, Velvety dark skin, AN.
In short
Acanthosis nigricans is thick, dark, velvety skin on the back of the neck, underarms, groin or knuckles. It is most often a skin sign of insulin resistance, linked to excess weight, PCOS or diabetes, and it is not caused by dirt and cannot be scrubbed away. Treating the underlying cause, along with treatment guided by a dermatologist, is what helps it fade.
Typical signs
- Dark, thick, velvety skin on the back or sides of the neck
- Similar darkening in the underarms, groin or under the breasts
- Darker skin over the knuckles
- Small skin tags in or around the dark areas
When to see a dermatologist
- You notice dark, velvety skin on your neck, underarms or groin
- Patches appeared suddenly, are spreading quickly or involve the palms, lips or mouth
- You also have irregular periods, acne, excess hair or weight gain
- You have a family history of diabetes and have not had your blood sugar checked
- The skin is itchy, smelly, painful or not improving
Signs vary from person to person and several skin conditions look alike. Only an examination can confirm a diagnosis.
Read the guides
Full, referenced articles on acanthosis nigricans written for Indian skin, with answers to common questions.
PCOS Skin and Hair Symptoms: A Complete Guide for Women
PCOS often shows on the skin first, as acne, facial hair, dark neck patches or thinning hair. Learn why it happens, what helps and when to get tested.
Excessive Facial Hair in Women (Hirsutism): Causes and Options
Thick, dark hair on a woman's face, chest or tummy is called hirsutism. PCOS is the most common cause. Here is how it is assessed and the treatment options.
Skin Care for Diabetes: Infections, Dry Skin and Foot Care
Diabetes raises the risk of skin infections, itchy dry skin, dark velvety patches and foot ulcers. Learn daily skin and foot care and when to see a doctor.
Dark Knees, Elbows and Lips: Causes and What Helps
Dark knees, elbows, knuckles and lips are common on Indian skin. Friction, dryness, sun, insulin resistance and lip habits play a role. What helps.
Hair Fall in Women: Causes, Tests and Treatment in India
Hair fall in Indian women is usually shedding after illness, stress or childbirth, or slow thinning linked to genes, iron, thyroid or PCOS. How to tell which.
Hormonal Acne in Women and PCOS: Signs, Causes and Treatment
Hormonal acne in women usually sits on the jaw and chin and flares before periods. Learn how PCOS is linked, which tests help and what treatment options exist.
Laser Hair Reduction on Indian Skin: Safety, Sessions, Risks
Laser hair reduction can be safe on Indian skin with the right device and settings. Expect around 6 sessions and long term reduction, not permanent removal.
Worried about acanthosis nigricans?
Book an online consultation with Dr. Maria Ansari for an assessment and a written care plan made for you.
This page is a short summary for general education and does not replace a consultation with a qualified dermatologist. Do not start, stop or change any medicine based on this page. Read the full medical disclaimer.