Acanthosis Nigricans is a benign dermatologic condition in which velvety grey-brown or black plaques develop on the skin. It generally occurs in areas of skin folding such as the back of the neck, armpits, or groin.
It is associated with a variety of endocrine disorders such as Addison's Disease, Cushing's Disease, and hypothyroidism. Rarely, acanthosis nigricans occurs in the setting of cancer or in association with other uncommon genetic syndromes. The most common cause, however, is insulin-resistant states such as diabetes mellitus. In addition, there is an association with obesity, itself a contributing factor to insulin resistance.
The exact cause of acanthosis nigricans is poorly understood. It is thought that high levels of insulin (as seen in diabetic patients) stimulate growth receptors in certain skin cells, leading to the characteristic hyperpigmented plaques. Acanthosis nigricans treatment is generally affected by addressing the underlying cause, most commonly obesity or elevated blood sugar. The simplest and most effective means of combating these problems are diet and exercise.
Decreasing overall caloric intake while maintaining a low-fat, high-fiber diet will help patients lose weight. This, in turn, will help reduce blood sugar levels. The addition of an aerobic exercise program to a balanced diet will help to further aid weight loss and blood sugar reduction.
Occasionally, if patients are unable to achieve satisfactory results with these first-line acanthosis nigricans treatment strategies, medications may be required to assist in maintaining normal blood sugar levels. As weight falls and blood sugar normalizes, the condition generally resolves.
