Acanthosis nigricans

"Acanthosis nigricans is a skin sign that can signal the presence of a number of underlying conditions. It is crucial to seek medical attention to identify and properly treat these problems."


What is acanthosis nigricans?

Acanthosis nigricans is a dermatological condition characterized by hyperpigmentation and thickening of the skin, which appears mainly in areas of the body with folds and wrinkles, such as the elbows, armpits or neck. This problem affects people of all ages, although it is more common in adulthood and in overweight or obese individuals.

Acanthosis nigricans is not a disease in itself, but rather an indicator of a possible alteration in the body. One of the most common causes is insulin resistance, a pre-diabetic condition that leads the body to produce more insulin than normal to compensate for the cells' inability to use it properly. The excess insulin stimulates the growth of skin cells, causing the characteristic symptoms of acanthosis nigricans to appear.

Although insulin resistance is one of the most common causes, there are other conditions that can trigger acanthosis nigricans. These include hormonal disorders, such as polycystic ovary syndrome; endocrine diseases, such as hypothyroidism or acromegaly; and even some medications, such as glucocorticoids and hormonal contraceptives.

What are the symptoms of acanthosis nigricans?

Acanthosis nigricans or acanthosis nigricans is characterized by the appearance of areas of thickened and darkened skin, often described as velvety to the touch.

These hyperpigmented areas usually develop in the skin folds, particularly in the neck region, armpits, elbow creases, knees, groins and, in some cases, hands, feet and lips.

The pigmentation may vary in color from light brown to black and, on rare occasions, may be accompanied by itching or have an unpleasant odor. The thickening of the skin may be mild to moderate, but is usually sufficient to give the affected areas a rough appearance. The distribution pattern is usually symmetrical, affecting both sides of the body equally.

In addition to skin changes, acanthosis nigricans may be associated with other signs and symptoms, depending on the underlying cause of the condition. For example, if it is related to insulin resistance, the person may have signs of type 2 diabetes, such as intense thirst, frequent urination, fatigue, and blurred vision. If acanthosis nigricans is caused by a hormonal disorder, symptoms of that disorder will also be present.

Acanthosis nigricans is itself a symptom of an underlying disorder, rather than a disease. Therefore, it is essential to seek medical attention if signs of acanthosis nigricans are observed to identify and treat the underlying cause, which can prevent progression of the condition and its possible complications.

Do you have these skin blemishes?

You may have acanthosis nigricans

What are the causes of achalasia?

Acanthosis nigricans can be a sign of a number of underlying disorders, including insulin resistance, endocrine disorders and certain types of cancer.

Insulin resistance is one of the most common causes of acanthosis nigricans. The body produces insulin, but the cells do not respond effectively to it. Consequently, the body produces more insulin to compensate, and elevated insulin levels can promote the overgrowth of skin cells, resulting in the characteristic appearance of acanthosis nigricans.

Endocrine disorders may also be linked to acanthosis nigricans. Diseases such as Cushing's syndrome, hypothyroidism, polycystic ovary syndrome or acromegaly can cause the appearance of this skin condition due to the abnormal production of various hormones that can affect the skin.

In addition, although less common, acanthosis nigricans can be a sign of certain types of cancer, especially lymphomas, tumors of the gastrointestinal tract or liver. In these cases, the appearance of acanthosis nigricans tends to be rapid and more extensive.

Finally, certain medications, such as glucocorticoids, hormonal contraceptives and some chemotherapy drugs, can trigger acanthosis nigricans by interfering with the body's normal metabolic pathways and altering skin growth and pigmentation.

Relationship between acanthosis nigricans and insulin resistance

Insulin is a hormone produced by the pancreas that plays a crucial role in regulating carbohydrate and fat metabolism. Under normal conditions, insulin facilitates the entry of glucose into cells to be used as energy. In insulin resistance, this mechanism is compromised: the body's cells become less sensitive to the effects of insulin, leading the pancreas to produce and release increasing amounts of this hormone in an attempt to maintain metabolic balance.

The relationship between acanthosis nigricans and insulin resistance lies in the effects this excess insulin has on the body. Elevated insulin levels in the blood can stimulate the proliferation of keratinocytes and fibroblasts in the skin, overgrowth of which leads to the hyperpigmentation and thickening characteristic of acanthosis nigricans.

In addition, insulin has a growth-promoting effect on various tissues in the body, including the skin. When there is insulin resistance, insulin levels in the bloodstream are elevated, and this excess insulin can act on insulin receptors in the skin, resulting in thickening and darkening of the skin.

Importantly, Acanthosis Nigricans, in this context, may be an early cutaneous marker of insulin resistance, even before other clinical signs of metabolic disorders, such as type 2 diabetes, become apparent.

How is acanthosis nigricans diagnosed?

The first step in diagnosing achalasia is a detailed medical history and physical examination. The doctor will ask about symptoms, their duration, and any factors that make them worse or better.

There are several tests that physicians can use to diagnose achalasia, including:

  • Esophageal Manometry: This test measures the pressure in the esophagus and can show if the lower esophageal sphincter is working properly.
  • Barium X-ray: During this test, the patient is asked to swallow a barium solution. X-rays are then taken to see how the barium flows through the esophagus.
  • Endoscopy: This procedure uses a thin, flexible tube with a camera to examine the esophagus and stomach.

How is acanthosis nigricans treated?

Treatment of acanthosis nigricans focuses primarily on addressing the underlying cause of this dermatologic condition, in addition to improving the appearance of the affected skin. Since acanthosis nigricans is often associated with conditions such as insulin resistance, obesity and certain endocrine disorders, therapeutic efforts are directed at treating these concomitant disorders.

In the case of insulin resistance, treatment may involve lifestyle changes, such as adopting a healthy diet and engaging in regular physical activity to improve the body's sensitivity to insulin. If acanthosis nigricans is associated with obesity, weight loss may reduce skin manifestations. Antidiabetic medications, such as metformin, may also be effective in managing insulin resistance and, therefore, may improve acanthosis nigricans.

If the acanthosis is caused by an endocrine disorder, it is essential to treat the underlying disease. This may involve adjusting existing medication or introducing new drugs to correct the hormonal imbalance.

In terms of treating the cutaneous manifestations of acanthosis nigricans, there are several options available. Topical retinoids, such as tretinoin, may be helpful in decreasing skin thickening. Salicylic acid and lactic acid creams may also be effective. In addition, dermabrasion and laser treatment can be used to improve the appearance of the skin.

Where do we treat it?


The Department of Dermatology
of the Clínica Universidad de Navarra

The Department of Dermatology of the Clinica Universidad de Navarra has extensive experience in the diagnosis and treatment of dermatological diseases.

We have extensive experience in highly precise surgical treatments, such as Mohs surgery. This procedure requires highly specialized personnel. 

We have the latest technology for the dermo-aesthetic treatment of skin lesions, with the aim of achieving the best results for our patients.

Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clinica?

  • Experts in Mohs Surgery for the treatment of skin cancer.
  • We have the best technology for dermo-aesthetic treatments.
  • Safety and quality assurance of the best private hospital in Spain.

Frequently asked questions about acanthosis nigricans

Not necessarily. Acanthosis nigricans often improves by treating the underlying cause. For example, weight loss and blood sugar control may reduce the occurrence of this condition in people with insulin resistance or diabetes.

No, acanthosis nigricans is not a contagious condition. It develops due to internal body factors, such as insulin resistance, endocrine disorders or certain medications, and cannot be passed from one person to another.

Yes, acanthosis nigricans can be a sign of underlying diseases, including type 2 diabetes, endocrine disorders, obesity and, in rare cases, certain types of cancer.

Prevention of acanthosis nigricans involves controlling associated risk factors, such as maintaining a healthy weight, following a balanced diet, and exercising regularly to prevent insulin resistance. Early detection and treatment of underlying disorders can also help prevent the onset of this condition.

If you suspect you have acanthosis nigricans, you should consult a dermatologist.

Depending on the underlying cause, it may also be necessary to consult other specialists, such as an endocrinologist or internist.