What is Acanthosis Nigricans, treatment, symptoms and more


What is Acanthosis Nigricans

Acanthosis Nigricans is a skin condition characterized by dark patches with a velvety texture that usually appear in the folds of the skin. This condition is not considered as a disease, but as a symptom of other possible ones, such as diabetes or cancer . The characteristic spots of Acanthosis Nigricans can appear in the following places on the body:

  • Armpits;
  • Groin;
  • Neck;
  • Elbows;
  • Knees;
  • Ankles;
  • Hips (lateral region of the body);
  • Palms;
  • Sole of the feet.

Index – in this article you will find the following information:

  1. What is Acanthosis Nigricans
  2. Types of Acanthosis Nigricans
  3. What are the causes?
  4. Groups of risk
  5. Symptoms of Acanthosis Nigricans
  6. How the diagnosis is made
  7. Treatment for Acanthosis Nigricans
  8. Are there complications?
  9. Prevention

Types of Acanthosis Nigricans

There are currently two divisions in place to differentiate the types of Acanthosis Nigricans – benign and malignant – and each is based on the types of the cause of the condition.

Benign type

This type of Acanthosis Nigricans includes the following causes:

  • Obesity;
  • Heredity;
  • Endocrine disorders.

Malignant type

The malignant type of the condition is more rare to happen, but there are chances of it manifesting as well. The malignant causes of Acanthosis Nigricans are:

  • Tumor;
  • Insulin activity in the body.

What are the causes?

As already described, Acanthosis Nigricans is subdivided into two types, according to their cause. Below, you will be able to better understand the reason why each one causes this skin condition in the patient.


The most frequent cause of this dysfunction, Acanthosis Nigricans can appear due to the excess of insulin that is in the blood system of the obese individual. In the normal body process, when a person eats, the body turns carbohydrates into sugar molecules, such as glucose. Therefore, the hormone insulin has the function of allowing glucose to enter cells, so that they can use it for their energy.

Overweight people, as time goes by, tend to develop insulin resistance, which ends up causing the body not to use the hormone correctly. Thus, insulin accumulates in the body and causes skin cells to reproduce very quickly, causing the epidermis – the outermost layer of the skin to darken.

Hereditary genes

The condition is passed on through an autosomal dominant pattern, that is, even if only one of the patient’s parents has the defective gene, there is a chance that he will develop this skin dysfunction. Despite this finding, there are rare cases in which Acanthosis Nigricans occurs due to a defective gene inherited from the parents.

Use of certain medications and supplements

The continued use of some types of substances can cause dark spots in certain areas of the body, such as birth control pills, growth hormones, medications that control the thyroid and even some bodybuilding supplements . This is due to the fact that these drugs increase the insulin level of the patient’s body.

Hormonal disorder

Acanthosis Nigricans can also be associated with some hormonal syndromes and / or disorders, such as:

  • Polycystic ovary syndrome: this condition affects the way the ovaries work, which ends up causing irregular menstrual periods, infertility, acne and weight gain;
  • Cushing’s syndrome: symptoms such as weight gain, black spots and stretch marks are caused by the high level of the hormone cortisol in the body;
  • Acromegaly: a condition that causes a significant increase in the secretion of growth hormone, causing an excessive growth of various tissues in the body;
  • Hypothyroidism: happens when the thyroid gland does not produce enough hormone, causing symptoms such as weight gain and tiredness.


If the dark spots characteristic of Acanthosis Nigricans appear very quickly on your body, perhaps this could be a sign of some cancer, such as stomach cancer. Because it is a rare condition, it tends to affect middle-aged or elderly people, and the spots are more serious, and can also appear on the mouth, tongue and lips.

Groups of risk

As much as this skin dysfunction can affect men and women in the same proportion, there are some risk groups that tend to develop Acanthosis Nigricans more easily. Are they:

  • Obese;
  • Black people or people of African descent;
  • Family history.

Symptoms of Acanthosis Nigricans

The main symptom of Acanthosis Nigricans is the appearance of spots with a darker color and dry and rough texture, which may even resemble velvet. These spots usually develop slowly, so you must always be aware of their appearance. In addition, there may be the appearance of small warts from these spots – also known as papillomatosis.

How the diagnosis is made

In cases of sudden appearance of spots that resemble Acanthosis Nigricans, the doctor to be consulted is the dermatologist, specialist in diseases and skin conditions. As this condition is very easy to recognize, the diagnosis is usually made through clinical analysis, but some tests can be ordered as well – to find out the exact cause of the spots. Among these tests are: blood glucose test, insulin test, skin biopsy, endoscopy and x-ray .

During the consultation, it is important that you tell the doctor what medications you take and the dietary, dietary and vitamin supplements you usually consume. Depending on what they are, the cause of Acanthosis Nigricans can be diagnosed more easily.

Treatment for Acanthosis Nigricans

There is no specific way to treat Acanthosis Nigricans, as it is not a disease, its treatment varies according to its causes. For example:

  • If the blemishes are caused due to the patient’s obesity, the doctor will probably indicate certain diets for him to be able to lose weight healthily;
  • Use of medications that correct your level of hormones;
  • Changing the medication if it triggers the symptoms of Acanthosis Nigricans;
  • Surgery, chemotherapy or radiotherapy in cases of cancer.

For cases where the spots are very unpleasant or embarrassing, the doctor may prescribe the use of some cosmetics, which will make these dark spots lighter. For this type of treatment, the dermatologist may recommend the use of Retin-A , with 20% urea in its composition, in addition to alpha-hydroxy acids and salicylic acid .


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Are there complications?

People who acquire Acanthosis Nigricans are more susceptible to developing type 2 diabetes.


For this skin condition to be prevented, maintaining healthy habits, as well as a good quality of life, already helps. Having a healthy lifestyle not only reduces the risk of getting Acanthosis Nigricans, but also different types of diseases.

In addition, sharing this information is also essential. Therefore, help us to spread more and more about Acanthosis Nigricans so that people less informed about the subject can know what this condition is.