In acanthosis nigricans, the skin becomes thick and velvety. It may appear gray, brown, or black. Common areas include the armpits, neck, under the breast, and more. It is often a sign of an underlying condition, such as insulin resistance.
Treatment usually involves addressing the underlying disorder, although some cosmetic and topical approaches may help improve symptoms.
In this article, we discuss treatment options for acanthosis nigricans, as well as the symptoms, causes, and links with other conditions.
There is no specific treatment for acanthosis nigricans.
While some cosmetic treatments may help, the most effective approach is to treat any underlying disorder. Addressing an underlying condition may cause symptoms to fade in time.
Treating the symptoms
To reduce the appearance of acanthosis nigricans, some people try topical or cosmetic treatments.
Examples of topical creams and ointments are:
- retinoids containing a combination of tretinoin
- ammonium lactate, which people may use with a topical retinoid
- podophyllin, which doctors also use to treat warts
- vitamin D analogs, such as calcipotriol (calcipotriene), which reduce the production of keratinocyte
Cosmetic procedures that may help include:
- dermabrasion, a type of exfoliation
- alexandrite laser, a type of red light laser with a specific wavelength of 755 nanometers
- chemical peels
Other options that may help
- fish oil
- topical creams containing urea or salicylic acid
- triple-combination skin-lightening cream containing tretinoin, hydroquinone, and fluocinolone acetonide
- using a sunscreen
Some of these treatments have helped improve symptoms in some people. However, the most effective approach is likely to be treating any underlying condition.
People should talk with their doctor before using any of these products.
Treatment for underlying conditions
Treatment for an underlying condition will depend on the issue.
- Hormone disorders: A treatment plan involving medication and lifestyle adjustments may help balance hormones and reduce symptoms of acanthosis nigricans.
- Diabetes: People with type 2 diabetes may need medications, monitoring of blood sugar levels, and some dietary and lifestyle adjustments. Once insulin levels become stable, acanthosis nigricans symptoms may resolve.
- Weight management: Obesity is a risk factor for insulin resistance and other aspects of metabolic disorder. Maintaining a moderate weight may help manage these conditions. In turn, skin symptoms may improve.
- Avoiding certain medications: Some drugs, such as corticosteroids, can trigger acanthosis nigricans. Symptoms often resolve if the person stops using the drug.
If acanthosis nigricans results from a hereditary disorder, the patches may grow slowly then stop or reduce in size without treatment. However, the changes will remain in most cases while the underlying condition is present.
Treating the underlying condition may improve symptoms of acanthosis nigricans. If a person with obesity loses weight, the patches may fade. However, changes in color may not disappear completely.
Treating skin symptoms will not make the lesions disappear. However, it may help improve the appearance.
Acanthosis nigricans often indicates that an underlying disorder is present. The changes take place when certain skin cells reproduce too quickly, leading to hyperpigmentation and hyperkeratosis.
Hyperpigmentation is when pigment increases in certain areas of skin, making them darker.
Hyperkeratosis is when the outer layer of skin becomes thicker due to the body producing extra keratin.
The following factors can cause acanthosis nigricans:
Hereditary acanthosis nigricans may be present from birth. However, most people develop it during childhood or later in life.
Unilateral acanthosis nigricans, also called nevoid acanthosis nigricans, is an inherited condition that causes symptoms on one side of the body. Some insulin-resistant syndromes with genetic causes can cause it, such as Rabson Mendenhall syndrome.
Drugs that may trigger acanthosis nigricans include:
- systemic glucocorticoids
- combined oral contraceptive pill
- growth hormone therapy
- protease inhibitors
- niacin (nicotinic acid)
- injected insulin
Acanthosis nigricans can develop with some types of cancer. Skin changes may appear before, during, or after internal symptoms become evident.
Some auto-immune conditions
According to the American Academy of Dermatology, people of Native American, Caribbean, African, or Hispanic descent are more likely to develop acanthosis nigricans.
The main symptoms of acanthosis nigricans are hyperpigmentation and hyperkeratosis. A person may notice changes in the color and texture of their skin. The color may become gray, black, or brown. The appearance and texture may become velvety.
The changes usually take months or years to appear. If they appear quickly, they could be a sign of cancer. The lesions may also be more widespread and more noticeable.
The person may also notice:
Some people experience these skin changes on one side of their body only. This is known as unilateral acanthosis nigricans.
Changes to the skin typically develop slowly. Occasionally, they can be present from birth. However, they usually appear in childhood or adulthood. They can occur anywhere but commonly affect the following:
- neck folds, especially on the back and sides of the neck
- under the breasts
- belly button
- palms of the hands
- soles of the feet
In rare cases, typically those associated with malignancy, skin changes of acanthosis nigricans
- areolae, around the nipples
- mucous membranes, including those in the mouth, nose, and throat
- part of the eye and eyelids
The following images show how acanthosis nigricans can appear on the skin.
- stomach cancer
- colon cancer
- liver cancer
- breast cancer
- ovarian cancer
- less commonly, with lung cancer, prostate cancer, and lymphoma
The symptoms of malignant acanthosis nigricans are similar to those of the benign form. However, they may be more severe and widespread and often develop more quickly. They can also affect the mouth and the area around the eyes.
Symptoms may appear before, during, or after other cancer symptoms.
Insulin resistance, a feature of type 2 diabetes, is linked to acanthosis nigricans. When people have insulin resistance, their bodies can no longer process glucose effectively.
The body produces more insulin in an attempt to manage this, resulting in high levels of both insulin and glucose in the body. These high levels of insulin can cause skin cells to reproduce
Research suggests that acanthosis nigricans may affect
Dark patches on the skin may be an early sign of type 2 diabetes. Anyone who notices these skin changes should seek medical advice, as they may need treatment to prevent or manage type 2 diabetes.
Acanthosis nigricans often occurs with PCOS. It happens when there is an imbalance in reproductive hormones. Symptoms include irregular menstruation and weight gain.
PCOS is a reproductive and metabolic disorder, and people with this condition often have insulin resistance.
People with PCOS have a higher chance of developing acanthosis nigricans. Insulin resistance appears to be a major factor. However, having obesity at the same time can further increase the risk.
People who notice skin darkening, thickening, or other skin changes should make an appointment to see their doctor. The changes are often harmless. However, they can suggest a medical condition that needs treatment.
A doctor can often diagnose acanthosis nigricans by looking at the skin. However, they may need to perform additional tests, such as a biopsy, to confirm the diagnosis.
They may also do blood tests, imaging scans, and other investigations to identify an underlying cause.
Acanthosis nigricans involves skin changes leading to patches of dark, thick, and velvety skin. These may appear on the neck, underarms, skin folds, and other parts of the body.
Obesity and insulin resistance are risk factors. However, hormonal disorders, medication use, cancer, and other conditions can cause it.
People who notice skin changes should see their doctor, as they may need treatment for an underlying disorder. Treating an underlying condition may improve skin symptoms. Some topical and cosmetic treatments may also help.