II. 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

III. 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

IV. 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

V. References

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Ontology: Acanthosis Nigricans (C0000889)

Definition (NCI) A melanotic cutaneous lesion that develops in the axilla and other body folds. It may be idiopathic, drug-induced, or it may be associated with the presence of an endocrine disorder or malignancy.
Definition (MSH) A circumscribed melanosis consisting of a brown-pigmented, velvety verrucosity or fine papillomatosis appearing in the axillae and other body folds. It occurs in association with endocrine disorders, underlying malignancy, administration of certain drugs, or as in inherited disorder.
Definition (CSP) circumscribed melanosis consisting of a brown pigmented, velvety verrucosity or fine papillomatosis appearing in the axillae and other body folds; occurs in association with endocrine disorders, underlying malignancy, administration of certain drugs, or as in inherited disorder.
Concepts Disease or Syndrome (T047)
MSH D000052
ICD10 L83
SnomedCT 402599005, 72129000
Italian Acantosis nigricans, Acantosi nigricans
Japanese 黒色表皮腫, コクショクヒョウヒシュ
Swedish Acanthosis nigricans
English ACANTHOSIS NIGRICANS, keratosis nigricans, acanthosis nigricans (diagnosis), acanthosis nigricans, Acanthosis Nigricans [Disease/Finding], Nigricans, Acanthosis, Nigrican, Acanthosis, Acanthosis Nigrican, Acanthosis nigricans, Keratosis nigricans, AN - Acanthosis nigricans, Acanthosis nigricans (disorder), keratosis; nigricans, nigricans; keratosis, Acanthosis Nigricans
Czech Acanthosis nigricans
Finnish Acanthosis nigricans
Korean 흑색 가시세포증(극세포증)
Croatian ACANTHOSIS NIGRICANS
Polish Rogowacenie ciemne
Hungarian Acanthosis nigricans
Norwegian Acanthosis nigricans
French Dystrophie papillaire et pigmentaire, Acanthosis nigricans
Dutch keratose; nigricans, nigricans; keratose, acanthosis nigricans, Acanthosis nigricans
Spanish acantosis nigricans (trastorno), acantosis nigricans, queratosis nigricans, Acanthosis nigricans, Acantosis Nigricans
Portuguese Acantose nigricans, Acantose Nigricans
German Acanthosis nigricans
Russian ACANTHOSIS NIGRICANS