About Acanthosis Nigricans

Overview

Acanthosis nigricans is a common skin condition where dark, thick patches of skin form, usually in body folds like the armpits or groin. Sometimes, these dark areas can also appear on the vulva. The affected skin often feels thick and soft, like velvet. Acanthosis nigricans is often linked to underlying health issues like polycystic ovary syndrome (PCOS), certain hormone-based medications, or issues with insulin (the hormone that controls blood sugar). It’s more common in people who are Native American, as well as African-, Caribbean-, or Hispanic-descent; and in those with a family history of the condition. It is also common for those who are overweight or have diabetes or prediabetes. Treatment usually focuses on addressing the underlying cause and managing insulin levels. In some cases, medications may be prescribed to help control blood sugar.

Causes and Risk Factors

Acanthosis nigricans (AN) is a skin condition characterized by dark, thickened patches of skin. It can occur in various areas of the body, such as the neck, armpits, groin, and elbows. The causes of AN can be both non-modifiable and modifiable risk factors. Let's take a closer look at each:

Non-modifiable risk factors for acanthosis nigricans, which are factors that cannot be changed to lower the chances of getting the disease, include:

Insulin Resistance: AN commonly affects people with obesity and insulin resistance. Insulin resistance means that the body cannot use insulin effectively. This can eventually lead to type 2 diabetes.
Hormonal Changes: People with hormonal disorders like Addison's disease, PCOS, or hypothyroidism may develop AN.
Genetic Factors: AN can be hereditary, meaning it can be passed down in families. Some people are born with it, but most develop it in childhood or later. There’s a specific inherited type called unilateral or nevoid acanthosis nigricans, which causes dark, thick patches to appear only on one side of the body.
Race: Race can also be a factor in the development of AN. It is most common in Native Americans, followed by African-Americans, Hispanics, and Caucasians.
Medication Use: Certain medications can cause AN. These include steroids (like glucocorticoids), hormone therapies (such as estrogen or growth hormone), some birth control pills, protease inhibitors (used for certain viral infections), niacin (a form of vitamin B3), and injected insulin.
Cancer: AN can develop with certain types of cancer. Skin changes may appear before, during, or after internal symptoms become evident.

Modifiable risk factors for acanthosis nigricans, which are factors that can be changed to lower the chances of getting the disease, include:

Obesity: People who are obese are more likely to develop AN. Research has shown that more than half of adults who weigh over 200 percent of their ideal body weight have AN.
Diet: Studies have found a link between AN and dietary factors such as increased intake of added sugar and servings of carbohydrate-rich foods. An increase in these dietary factors can increase the risk of developing AN.

Understanding the causes and risk factors associated with acanthosis nigricans can help individuals take proactive steps to manage their health and reduce their risk of developing this skin condition.

Symptoms

Here are the most common early symptoms of acanthosis nigricans:

Hyperpigmentation: The affected areas of the skin may become darker in color, appearing gray, black, or brown.
Hyperkeratosis: The texture of the skin may become thick and rough, resembling a velvet-like appearance.

In addition to these early symptoms, there are other common symptoms that may occur with later stages, progression, or higher severity of acanthosis nigricans:

Dryness: The affected skin may become dry and flaky.
Itching: Some individuals may experience itching in the affected areas.
Unusual odor: Acanthosis nigricans can sometimes cause an unusual odor in the affected skin.
Skin tags: Skin tags, which are small, soft growths that hang off the skin, may develop in the affected areas.
Nail changes: In some cases, acanthosis nigricans can cause changes in the nails, such as thickening or discoloration.

It's important to note that symptoms can be different depending on the individual. If you experience any of these symptoms, it is recommended to consult with a healthcare professional for an accurate diagnosis and appropriate treatment.

Diagnosis

To diagnose acanthosis nigricans, health care providers commonly perform the following examinations, tests, and procedures:

Physical Exam: The doctor will examine the skin to check for dark, thick, and velvety patches, which are common signs of AN. They may also look for other health issues, like weight gain or hormone imbalances, which can be linked to AN.
Lab Tests: Blood tests might be done to check for related health issues, such as high blood sugar or insulin levels, which can be signs of diabetes or insulin resistance. Blood tests may also look at hormone levels if a hormone issue is suspected.
Imaging Studies: If AN appears suddenly and is very noticeable, imaging tests like an ultrasound, CT scan, or MRI might be recommended to check for any tumors or internal issues that could be causing the symptoms.
Clinical Procedures: In some cases, a small sample of the affected skin (a biopsy) may be taken to look at it under a microscope. This helps confirm if it’s AN and rules out other skin conditions.
Genetic Testing: In rare cases, genetic testing may be done if inherited types of AN are suspected, especially when AN appears only on one side of the body. This test can show if there’s a genetic reason behind it.
Follow-Up with Healthcare Provider: Regular checkups are helpful to watch for any changes in the skin or in health conditions linked to AN. The doctor may suggest lifestyle changes, treatments, or other steps based on individual needs.

It's important to note that the specific examinations, tests, and procedures recommended for each individual may vary based on their unique circumstances and symptoms. It's always best to consult with a health care provider who can provide personalized guidance and recommendations based on your specific situation.

Treatment Options

The goals of treatment for acanthosis nigricans are to correct the underlying disorder and improve the appearance of the skin. Here are some recommended treatments and how they work to achieve these goals:

Topical Medication: These are creams or ointments you apply directly to the affected skin. Examples include:

Topical retinoids and lactates: Help improve skin texture and color.
Topical vitamin A: Vitamin A creams can help reduce symptoms of acanthosis nigricans.
Topical keratolytics: These help exfoliate and soften thickened skin.

Therapies:

Laser Treatments: Lasers like pulsed dye laser (PDL) and long-pulsed alexandrite laser target and reduce skin pigmentation in affected areas.
Cryotherapy: This uses liquid nitrogen to freeze and remove affected skin cells. It can help, but may cause lighter spots or return of symptoms.

Therapeutic Procedures:

Skin Removal Techniques: Methods like curettage, excision, electrodessication, and dermabrasion physically remove affected skin cells, which can improve the skin's appearance.

Lifestyle Changes:

Weight Management: Keeping a moderate weight can help with conditions like insulin resistance, which often links to acanthosis nigricans.
Avoiding Certain Medications: Some drugs, such as corticosteroids, can worsen symptoms. Stopping these medications, if possible, may help reduce symptoms.

It's important to note that there is no specific treatment for acanthosis nigricans, and the most effective approach is to treat any underlying conditions that may be contributing to its development. By addressing these underlying conditions, symptoms of acanthosis nigricans may fade over time.