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Acanthosis Nigricans: Symptoms ,Causes Diagnosis And Treatment

May 01, 2023

Acanthosis Nigricans Symptoms ,Causes Diagnosis And Treatment

Acanthosis Nigricans

  • The skin darkening condition  known as acanthosis nigricans typically affects intertriginous regions. The axilla, groin, and back of the neck are common locations for this hyperpigmentation, which has ill-defined borders and may thicken the skin. Although acanthosis nigricans is most frequently linked to diabetes and insulin resistance, it can occasionally be an indicator of an internal malignancy. Additionally, it can happen when taking certain drugs like oral contraceptives and systemic glucocorticoids, as well as in cases of hormone disorders.


  • The emergence of acanthosis nigricans is influenced by a number of variables increased levels of insulin in the blood, which activates IGF-1 and other ILGF receptors on keratinocytes. Insulin may displace IGF-1 from the IGF binding protein at high quantities. Keratinocyte and dermal fibroblast proliferation may be caused by elevated levels of circulating IGF. Defects in fibroblast growth factor are linked to hereditary variations. Malignancy-related acanthosis nigricans appears to be caused by an increase in transforming growth factor (TGF). Through the epidermal growth factor receptor, TGF affects epidermal tissue.
  • Familial Acanthosis Nigricans: This condition may manifest at birth or during childhood as a result of an autosomal dominant feature. Mutations in the fibroblast growth factor receptor are the cause of Acanthosis nigricans. 
  • Obesity causing acanthosis nigricans: obesity is one of the most prevalent conditions connected to Acanthosis nigricans. Although they can happen at any age, lesions typically occur in adults. "Pseudoacanthosis nigricans" was originally the name given to it. Insulin resistance may be linked to it. Acanthosis nigricans can revolve if obesity is treated with diet, exercise, or pharmaceuticals. Drugs that may be used to treat acanthosis nigricans: 

Acanthosis Nigricans related to Medications

Using nicotinic acid, systemic glucocorticoids, diethylstilbestrol, the combination oral contraceptive pill, growth hormone therapy, oestrogen, protease inhibitors, niacin, and injectable insulin are a few of them.

Acanthosis Nigricans linked to Endocrine Dysfunction

Patients who are frequently fat, and in these patients the disease manifests itself more subtly. Type A (HAIR-AN) and type B syndromes are two categories for insulin-resistance syndromes. Acanthosis nigricans, insulin resistance, and hyperandrogenemia are all symptoms of type A syndrome. Women with uncontrolled diabetes, ovarian hyperandrogenism, or autoimmune diseases including SLE, Sjogren's syndrome, or scleroderma are more likely to develop type B syndrome. Acanthosis nigricans is linked to PCOS, or polycystic ovarian syndrome. Patients with PCOS exhibit insulin resistance and hyperandrogenic behaviour.

Acanthosis Nigricans due to Acral Acanthotic Anomaly

This  only affects the elbows, knees, knuckles, and dorsal surfaces of the foot is referred to as an acral acanthotic abnormality. It frequently affects those with dark complexion.

Unilateral Acanthosis nigricans

It is also known as nevoid Acanthosis nigricans. This condition is  very rare in this lesions occur unilaterally and can be present at any age i.e  infancy, childhood or adulthood.

Malignant Acanthosis nigricans syndrome

This syndrome is associated with carcinoma of gastrointestinal genitourinary tracts like prostate, breast, and ovary. Lung cancer and lymphoma rarely are also associated with acanthosis nigricans. It has a rapid onset and is associated  by skin tags, multiple seborrheic keratoses known as sign of Leser-Trelat or tripe palms.

Auto-immune Acanthosis Nigricans

It is  associated with autoimmune disorders like SLE, Sjogren's syndrome, scleroderma or Hashimoto's thyroiditis.

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Symptoms of acanthosis nigricans

  •  Hyperpigmented velvety thick skin in body folds and creases which appears in the armpits, groin region and back of the neck. It progresses slowly. The affected area skin might feel itchy, have an odor and we can see skin tags appearing on the upper surface near the borders.
Acanthosis Nigricans

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Causes of Acanthosis Nigricans

  • Insulin resistance. People Suffering from insulin resistance are more likely to develop acanthosis nigricans as Insulin is a hormone secreted by the pancreas and it allows the body maintain sugar levels to a normal range. Resistance of insulin leads to diabetes mellitus type 2. It is also related to polycystic ovarian syndrome.
  • Drugs and supplements. High-dose of niacin, oral contraceptives, anti-inflammatory drugs like prednisone and some corticosteroids may also lead to acanthosis nigricans.
  • Malignancy, lymphoma and gastric carcinoma, carcinoma colon and liver can also result in acanthosis nigricans.

Diagnosis of Acanthosis nigricans

  • It is diagnosed with a skin biopsy. Some Blood tests and some other investigations like endoscopy,  x-rays can also be required to analyze whether the person is suffering from diabetes or any other tumor. On biopsy we can find leukocyte infiltration, epidermal folding and melanocyte growth. Main focus is to rule out any malignancy. As most of the cases are associated with insulin resistance and obesity so glucose levels of the body should be checked.

Treatment of Acanthosis Nigricans

  • There is no cure for Acanthosis nigricans. It may resolve over time if we treat the cause i,e insulin resistance. We can do that by Controlling blood glucose levels of the body through regular exercise and dietary modifications which can help to  improve symptoms. Acanthosis  nigricans malignant can be resolved by surgical removal of tumors which can be the cause of acanthosis nigricans occurring in the person.
  • The main goal of treatment is to detect the underlying cause obese  patients, losing weight loss insulin resistance correction can lowers the hyperkeratotic lesions. Drugs which are insulin-sensitizing agents such as metformin and rosiglitazone can be used to decrease the symptoms. All medications which can lead to enhancement of symptoms should be discontinued. 
  • Melatonin can also help to improve skin symptoms in obese patients which are suffering from as it improves the inflammatory status of the body and also insulin sensitivity.
  • Cosmetic treatments such as chemical peels, laser, dermabrasion.
  • Surgical removal of the cancer is the main goal of treatment for malignant lesions.

Differential Diagnosis of acanthosis nigricans

  • Following are the differential diagnosis for acanthosis nigricans:
    • Seborrhea
    • Tinea
    • Erythrasma
    • Candidiasis
    • Pellagra
    • Ichthyosis
    • Linear epidermal nevus
    • Granular parakeratosis
    • Cutaneous hyperpigmentation related to Addison's disease

Complications of Acanthosis Nigricans

Acanthosis nigricans are as a result of some other underlying diseases so the complications depend on the underlying diseases. If the insulin levels are raised in the body so other complications apart from acanthosis nigricans can occur such as vision problems or even the nerve damage. Usually acanthosis develops slowly but if it had occurred rapidly then malignancy can be one of the causes of its rapid growth.


Usually Patients suffering from benign form of acanthosis nigricans usually have very  few and even no skin complications, so, good prognosis can be expected with treatment. Prognosis in case of patients with malignancy is poor.

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