Which clinical history findings are characteristic of acanthosis nigricans (AN)?

Updated: Oct 14, 2020
  • Author: Jason H Miller, MD; Chief Editor: William D James, MD  more...
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Patients usually present with an asymptomatic area of darkening and thickening of the skin. Pruritus occasionally may be present. Lesions begin as hyperpigmented macules and patches and progress to palpable plaques.

In approximately one third of cases of malignant acanthosis nigricans, patients present with skin changes before any signs of cancer. In another one third of cases, the lesions of acanthosis nigricans arise simultaneously with the neoplasm. In the remaining one third of cases, the skin findings manifest sometime after the diagnosis of cancer. Malignant acanthosis nigricans has been reported to appear abruptly and exuberantly and may be associated with a higher rate of pruritus. [1]

Onset may be related to medication or supplement usage.

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