Acanthosis Nigricans

Acanthosis Nigricans is a skin disorder characterized by darkening and thickening of the skin affecting the area of skin folds mainly armpits, posterior neck and groin. Acanthosis nigricans is usually cutaneous manifestation of underlying condition or disease. Several benign, harmless forms of acanthosis nigricans have been described in which the disorder may be inherited from their families or may be associated with various underlying syndromes, obesity, or certain medications use.

What causes Acanthosis Nigricans?

The definitive cause for acanthosis nigricans is still unclear but it is often associated with conditions that increase your insulin level, like obesity and type 2 diabetes. Most common cause of AN is associated with obesity. Some cases are inherited and some rare cases are associated with gastric cancer. Certain medications, especially hormones such as oral contraceptive and growth hormones and excess dose of vitamin B3 (niacin) may also contribute to this condition. Other endocrine disorders such as polycystic ovary syndrome (PCOS) and others may also contribute.

Symptoms of Acanthosis Nigricans

Skin changes are the only signs of acanthosis nigricans where darkening and thickening of the skin around armpits, posterior neck and groin occurs. The affected area usually doesn’t itch, but few cases may also be associated with mild itching. Skin tags may be found around the affected area. Skin changes are very slow and may take months to years. Lesions may also be seen on oral mocous membrane, nasal and esophagus. When its due to internal malignancies, the lesion tends to be more extensive and severe.

How is Acanthosis Nigricans Diagnosed ?

Diagnosis is usually made clinically during skin exams. If the clinical diagnosis is confusing, skin biopsy may be needed. It is very important to find the cause and differentiate if AN was cause by malignancies or some benign harmless condition.  If the cause is unknown, your doctor may perform x-ray, ultrasound or blood tests to find out other possible underlying cause.

Acanthosis Nigricans Treatment

The primary goal of the therapy is to treat the underlying conditions. Underlying cause or conditions such as obesity, excess insulin, tumors and medication should be avoided and treated accordingly.

There is no any specific treatment for acanthosis nigricans. Treatment of the lesion to improve cosmetic appearance can be achieved through topical medications such as retinoids, hydroquinone, dermabrasion and laser therapy. Oral medications, such as etretinate, isotretinoin, metformin, and some fish oils supplements have shown good results.

The outcome of acanthosis nigricans depends on the cause. If its due to internal malignancies than the outcome is very poor. However, AN due to change in lifestyle or drugs or other benign condition has good outcome once the causative factors is removed or treated.