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Acanthosis nigricans

What is it?

Acanthosis nigricans is characterized by the darkening of the skin in body folds and flexures, which becomes thick and velvety.

The disease can affect healthy people or may be associated with other health problems. Some cases are genetically inherited and it is more common the occurrence among people of African descent.

Obesity, as well as other endocrine disorders, can lead to the appearance of acanthosis nigricans, which is frequently found in people with diabetes.

Some drugs, like growth hormone or oral contraceptives are also cited as possible causes for the appearance of acanthosis. Severe cases may be related to the occurrence of malignancies, most commonly gastrointestinal or genitourinary tract, but its occurrence is rare.

Characteristics and symptoms

The acanthosis nigricans develops slowly causing gradual darkening of the affected areas and the lesions are not accompanied by other symptoms.

The places most affected are the armpits, groin and neck, on which are formed areas of darkened, rough ant thickened skin giving a velvety appearance. In some cases, the lips, palms, soles and other areas of the body may also be affected.


If the cause of the appearance of acanthosis nigricans is found and treated, the lesions tend to disappear. When the cause is not found, the use of local products derived from retinoids are an option for enhancing the aspect of the lesions and should be prescribed by a dermatologist according to each case.

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