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 healthcare provider.
Acanthosis Nigricans 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.
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
- Medications: 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. 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.
Report the symptoms of acanthosis nigricans to your healthcare provider, who will examine your skin and can usually diagnose it based on its appearance. Your practitioner 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.
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.
Frequently Asked Questions
What is acanthosis nigricans and what causes it?
Acanthosis nigricans are dark patches of thickened, velvety skin. It commonly appears on the neck, thighs, or vulva and is often confused at first with dirt-crusted skin.
Its exact cause is unknown, but it is associated with obesity, polycystic ovary syndrome, type 2 diabetes, genetic disorders, and certain cancers. You can have acanthosis nigricans without any other medical conditions.
Can you have acanthosis nigricans and not have diabetes?
Yes, acanthosis nigricans is more common in people with diabetes than in the general population. However, you may have acanthosis nigricans and not have diabetes.
Will acanthosis nigricans go away on its own?
If acanthosis nigricans is due to a medical condition, such as diabetes, treating the underlying disease can help clear up dark patches of skin. Weight loss and exercise to reverse insulin resistance can often fade acanthosis nigricans.
Should I see a dermatologist for acanthosis nigricans?
Yes, a dermatologist can offer specialized treatments for acanthosis nigricans. Treatments include topical retinoids, dermabrasion, or laser therapy.