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Acanthosis Nigricans

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Acanthosis Nigricans

  • See Also
  1. Skin Conditions in Diabetes Mellitus
  2. Necrobiosis Lipoidica diabeticorum
  3. Diabetic Dermopathy
  4. Granuloma Annulare
  5. Diabetic Ulcer
  6. Diabetes Mellitus
  7. Type I Diabetes Mellitus
  8. Type II Diabetes Mellitus
  9. Insulin Resistance Syndrome
  10. Glucose Metabolism
  11. Diabetes Mellitus Education
  12. Diabetes Mellitus Complications
  13. Diabetic Ketoacidosis
  14. Hyperosmolar Hyperglycemic State
  15. Diabetes Mellitus Control in Hospital
  16. Diabetes Mellitus Glucose Management
  17. Hypertension in Diabetes Mellitus
  18. Hyperlipidemia in Diabetes Mellitus
  19. Diabetic Retinopathy
  20. Diabetic Nephropathy
  21. Diabetic Neuropathy
  • Classification and Causes
  1. Type 1: Hereditary Benign Acanthosis Nigricans
    1. Idiopathic onset during childhood or Puberty
  2. Type 2: Benign Acanthosis due to Insulin Resistance
    1. Diabetes Mellitus
    2. Androgen Excess (Hyperandrogenism)
      1. Acromegaly (Gigantism)
      2. Cushing's Syndrome
      3. HAIR-AN Syndrome
    3. Hypogonadism
      1. Addison's Disease
      2. Hypothyroidism
  3. Type 3: Pseudo-Acanthosis Nigricans
    1. Obesity resulting in Insulin Resistance
    2. Seen in patients with darker pigmentation
    3. Specific findings
      1. Numerous Skin Tags in axilla and groin
      2. Velvety patch at inner upper thigh areas of chafing
  4. Type 4: Drug-induced Acanthosis Nigricans
    1. Nicotinic Acid (high dose)
    2. Glucocorticoids
    3. Diethylstilbestrol (DES)
    4. Oral Contraceptives (androgenic Progesterone)
    5. Growth Hormone therapy
  5. Type 5: Malignant Acanthosis Nigricans
    1. Causes
      1. Paraneoplastic tumors (Adenocarcinoma)
      2. Lymphoma
    2. Specific findings
      1. Palm and sole hyperkeratosis
      2. Lip vermilion border and Oral Mucosa involved
  • Signs
  1. Characteristics
    1. Hyperpigmentation patches (dirty-appearing)
    2. Velvety feel and appearance develops over time
  2. Distribution
    1. Nape of neck
    2. Axillae
    3. Groin
    4. Vulva and Perineum
    5. Antecubital fossa
    6. Knuckles
    7. Submammary region
    8. Umbilicus
  • Evaluation
  1. Consider malignancy
    1. Onset over age 35 years
    2. Non-obese patient
  2. Evaluate for cause of Insulin Resistance
  3. Evaluate for Hyperandrogenism
  • References
  1. Elmer (2001) Am Fam Physician 63(12):2385-90 [PubMed]
  2. Fitzpatrick (1992) Atlas Dermatology, McGraw, p.732-3
  3. Hacker (1996) Postgrad Med 99(6):177-86 [PubMed]