Options for Treating Acanthosis Nigricans

Medically reviewed by

on February 22, 2020

Acanthosis nigricans is patches of dark, thickened, velvety skin that can appear on the neck, on the thighs, or on the vulva. The condition itself isn't harmful or contagious, although you may not like its appearance. But since it can be a sign of other medical conditions, it is a concern to bring up with your doctor.

Causes

Acanthosis nigricans can be seen in otherwise healthy people, so it is not always related to a medical condition. However, it is associated with these conditions:

Obesity—the most common association; losing weight can reverse it
Genetic disorders, including Down syndrome
Cancers of the digestive tract, liver, kidney, bladder, or lymphoma (this is rare)
Polycystic ovary syndrome (PCOS) and ovarian cysts
Birth control pills, human growth hormone, high-dose niacin, prednisone, and some other medications
Type 2 diabetes—one 2016 study noted that more than half of children with type 2 diabetes have acanthosis nigricans, and adults with diabetes often develop it as well.

Insulin Resistance and Acanthosis Nigricans

Insulin resistance means that the body is not responding as well to insulin as it could be (this happens in people with PCOS and people who are pre-diabetic, for example). Insulin causes glucose to be taken into the body cells to be used for energy. Someone with insulin resistance will require larger and larger amounts of insulin to be secreted before glucose is taken into the body tissues, and eventually change the way the body deals with sugar. One of these ways is making extra pigment.

Signs and Symptoms

Dark, thickened, velvety skin slowly develops in areas of the body where there are skin folds, typically the armpits, groin, and the fold of the neck. Some people call the line on the neck the sugar line or sugar necklace (due to the association with diabetes). The pigmentation may also appear over the joints in the fingers and toes.

The skin stays soft, unlike some other syndromes where the skin toughens. Less often, pigmentation will appear on the lips, palms or soles, and more frequently that is associated with those who have cancer.

Diagnosis

Report the symptoms of acanthosis nigricans to your doctor, who will examine your skin and can usually diagnose it based on its appearance. Your doctor will also likely order blood tests for blood sugar level or insulin level. You may also undergo endoscopy or X-rays to check for cancer and other causes.

Treatment

Primary treatment of acanthosis nigricans aims to correct the underlying cause. Weight loss and reversing insulin resistance are the most effective ways to eliminate any skin changes. It is reversible and will disappear as the cause is treated.

There are cosmetic options if acanthosis nigricans is severe or not being managed by weight loss. Treatments include laser therapy, topical retinoids, and dermabrasion. Topical retinoids increase shedding of normal skin cells, which can reduce the appearance of the lesions. Both dermabrasion and laser therapy are procedures that should be performed only by a certified dermatologist.