What is Acanthosis Nigricans?

Acanthosis nigricans, also known as melanosis or pigmented papillary dystrophy, is a rare skin disease characterized by deeper skin color and papillary or velvety hyperplasia. Ollendorff Curth divides it into benign acanthosis without visceral tumors and malignant black acanthosis often associated with visceral adenocarcinoma.

Basic Information

nickname

Melanosis, pigmented papillary dystrophy

English name

acanthosis nigricans

Visiting department

dermatology

Common symptoms

Darkened skin, gray-brown or gray-brown, dry and rough surface

Causes of Acanthosis nigricans

It is not very clear, and may be related to many factors. It is generally thought that it may be the stimulation of the tyrosine kinase growth factor receptor signaling pathway in the epidermis. There is also evidence that insulin plays a role, and severe insulin resistance is often associated with acanthosis nigricans. The incidence of black acanthosis in women with hyperandrogenemia is 5% to 29%. Obesity is closely related to Acanthosis nigricans, and there is a positive correlation between the two. The change in the rash is not only related to the degree of obesity, but also decreases with weight loss.

Malignant Black Acanthosis: This disease is almost always associated with visceral tumors. About 60% of patients 'skin symptoms progress synchronously with the degree of visceral malignancy. About 20% of patients' skin symptoms precede the malignant tumor for several years. About 20% of patients have primary malignant tumors and secondary skin symptoms.

Clinical manifestations of acanthosis nigricans

The rash initially deepens the skin color and is grayish brown or grayish brown. The surface is dry and rough, and then the skin is thickened. The surface has many small nipple-like protrusions, which are velvety and soft to the touch. With the progress of the disease, the skin is thick, the skin lines are widened and deepened, there are papillary or wart-like nodules on the surface, and large verrucous vegetation can appear. Occurred in skin wrinkles, such as the neck, axilla, groin, under the nipple, umbilical fossa, external anal genitals and so on. Hyperkeratosis often occurs in palms. Sometimes seen on the face, elbows, knees and digit extensions. The disease is divided into 8 types, and all types of rashes are basically the same, but the severity and the extent of the rash are different. In severe cases, almost all parts of the skin are affected.

Black echinoderma is mainly divided into the following eight types: benign echinoderma, obese echinoderma, symptomatic echinoderma, malignant echinoderma, acral echinoderma, unilateral echinoderma, drug-induced echinoderma , Mixed black acanthosis. Malignant black acanthosis is accompanied by malignant tumors, the most common of which are abdominal malignancies.

Malignant black acanthosis occurs in middle-aged and elderly people and is rare in children. The rash develops rapidly, extensively, and severely, often involving the mucous membranes, extremities can also be affected, hyperkeratosis of the palms and palms, pigmentation is more pronounced, and it is not limited to the hyperkeratotic skin lesions. This type is often accompanied by three skin disorders of visceral tumors: Leser-Trelat sign, hyperkeratosis of palmar plantar, and bright red skin papillomatosis, suggesting that the four have a common pathogenesis. Most of the associated visceral tumors are adenomas, of which gastric cancer is the largest, followed by pancreatic cancer, hepatobiliary cancer, breast cancer, bowel cancer, uterine cancer, and ovarian cancer. The rash is closely related to tumors. Recent studies have found that most rashes occur before tumors. The rash decreases with tumor resection and treatment, and recurs with tumor recurrence and metastasis.

Black Acanthosis Diagnosis

Diagnosis is not difficult according to the gray-brown or gray-black papillary or velvet-like thickening of the skin in the wrinkled areas such as the neck, armpits, and groin.

Acanthosis nigricans treatment

First, we should actively look for the cause. For patients with malignant echinoderma, it is necessary to actively search for visceral tumors and perform surgical resection. Cyproheptadine can also be used to inhibit the release of tumor products. For obese echinoderma, it is necessary to correct obesity, actively participate in physical exercise, control diet to lose weight, and as the weight decreases, echinoderma is cured. For those who cause the drug, all suspected disease-causing drugs should be stopped in time, and the rash can heal itself after stopping the drug. For patients with benign type, if the change of skin color and skin tags hinder beauty, surgery or electrocautery can be performed; for syndrome type, the main treatment is syndrome.

For topical treatment, keratolytic agents can be selected, such as salicylic acid, calcipotriol, vitamin D ₃ derivatives, urea, retinoic acid ointment, podophylline, etc., and continuous wave CO ₂ laser treatment can also be tried.