Randy Jacobs, M.D. Patient Education

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Acanthosis Nigricans

Randy Jacobs, M.D.



Acanthosis nigricans is a disorder that causes light-brown-to-black, velvety, rough areas or increased skin markings usually on the back and sides of the neck. The condition can also at times occur under the arms and in the groin. A skin condition characterized by increased pigmentation (darkening of the skin) and hyperkeratosis (thickening of the skin). It occurs most commonly in the flexural skin areas (behind knee, front of elbow, neck, etc.). The disorder is related to insulin metabolism and appears in diseases which affect insulin metabolism including obesity. In adults the condition may be associated with malignant tumors but is usually benign.



Acanthosis nigricans may begin at any age. We do not know the exact cause of this condition. Rarely the condition is associated with an endocrine disorder or a tumor. Most often acanthosis nigricans is associated with being overweight.



When acanthosis nigricans develops in people who are not overweight, a medical work-up should be done to determine whether or not the patient has a gland (endocrine) disorder or a tumor. Retin-A, 15% urea, lactic acid, and salicylic acid are all prescriptions that may provide some improvement for this condition. There is no cure for acanthosis nigricans. Overweight individuals usually have improvement if they lose weight. In those who have a tumor or a gland disorder, correction of the underlying problem will often cure the acanthosis nigricans.