Certified Diabetes Care and Education Specialist (CDCES) Practice Exam

Which of the following best describes the cause of acanthosis nigricans in an obese woman examined for dark pigmented skin?

1. Poor hygiene

2. Insulin resistance

3. Genetic predisposition

4. Metformin adverse effect

The correct answer is: Insulin resistance

Acanthosis nigricans is characterized by dark, velvety patches of skin, typically found in body folds such as the neck, armpits, and groin. In obese individuals, particularly women, one of the primary underlying causes of acanthosis nigricans is insulin resistance. This condition leads to elevated insulin levels, which can stimulate the proliferation of keratinocytes and increase the production of melanin by melanocytes, resulting in the thickened, pigmented skin characteristic of acanthosis nigricans. While poor hygiene, genetic predisposition, and metformin adverse effects might relate to skin changes in different contexts, they do not primarily account for the specific pathophysiology of acanthosis nigricans in the setting of obesity and metabolic disturbances. Poor hygiene may contribute to skin issues, but it is not a direct cause of this condition. Genetic predisposition might lead to a higher risk of developing insulin resistance and associated conditions but does not directly cause the darkening of the skin. Lastly, while metformin can have side effects, acanthosis nigricans is not commonly listed among them. Therefore, insulin resistance stands out as the best explanation for the observed skin changes.