Acanthosis nigricans is a skin disorder that causes patches of skin to appear light-brown to black, often in several areas of the body. It can affect anyone, but doctors regard it as a possible sign of an underlying condition. The markings look like a stain you could scrub off — yet washing will not remove them.
The most common sites are skin folds of the neck and armpits. In some cases it also appears in more private areas, such as the groin or under the breasts.
What causes acanthosis nigricans?
Acanthosis nigricans is generally linked with insulin resistance, in which the body's cells stop responding properly to insulin. It is often seen in people with type 2 diabetes, pre-diabetes, obesity, or metabolic syndrome. Other causes include the following.
- Hormonal disorders: such as thyroid disease, polycystic ovary syndrome, or Cushing's syndrome.
- Heredity: some people inherit the tendency from their parents.
- Medications: high-dose niacin, birth control pills, corticosteroids, and others may trigger it.
- Underlying cancer: in rare cases it may be associated with stomach or liver cancer.
When should you see a dermatologist?
Watch for changes in your skin colour, particularly darkening patches that grow or spread, and consult a dermatologist if this happens — acanthosis nigricans can be an early sign of a chronic internal disorder. Other signs and symptoms that warrant medical attention include:
- Brown or black patches on the skin.
- A velvety texture to the skin.
- Skin tags.
- Itchiness across the patches.
- Foul-smelling skin patches.
Treatment options for acanthosis nigricans
Treatment options are limited, so the dermatologist first examines the skin and may advise tests to identify the root cause. Once the cause is established, the priority is to treat the underlying condition. If diabetes or a hormonal disorder is responsible, treating it will also improve the acanthosis nigricans — which may mean seeing a cardiologist or an endocrinologist. You may also be advised to adjust your diet and lifestyle to lower insulin levels and improve the skin.
To further manage the symptoms, the dermatologist may recommend the following.
- Prescription creams: to lighten the dark patches. Some contain retinoids that help clear the skin, and consistent use may fade the discolouration.
- Laser therapy or dermabrasion: cosmetic procedures that target thick, dark patches to reduce their appearance.
- Prescription medications: including antibiotics to address odour or to manage discomfort such as itchiness.
- Medication review: if an existing medication is aggravating the condition, your dermatologist may advise adjusting the dose. Avoid self-medicating or using skincare products without consulting them.
Personalised, expert-led care
Because acanthosis nigricans often reflects a metabolic cause, we treat the skin and refer for the underlying work-up. At Derma Essence, treatment is led by Dr. Reena Sharma (MD Dermatology). For related concerns, see PCOS care or pigmentation treatment.
Book a consultation for a personalised assessment and metabolic screening.
