Table 2.

Etiology of AN

Obesity
Endocrine and metabolic disorders	Diabetes, polycystic ovarian syndrome
Genetic syndrome	Down syndrome, congenital lipodystrophy
Familial AN
Drug interaction	Systemic glucocorticoids, injected insulin, oral contraceptives, niacin, nicotinic acid
Malignancy	Abdominal adenocarcinoma, particularly gastric adenocarcinoma

Abbreviation: AN, acanthosis nigricans.