What is acanthosis nigricans?

What is acanthosis nigricans?

• A. Symmetric hyperpigmented plaques on skin in folds of the neck
• B. It is a fungal infection of nails
• C. It is a retinal vascular disease
• D. It is a type of joint disease

Answer: (A)

Acanthosis nigricans shows up as symmetric, hyperpigmented, velvety thickening of the skin in folds where skin rubs together, especially the neck, armpits, and groin. This description fits the given choice. It’s commonly tied to insulin resistance and obesity, and in adults it can be a sign of an underlying malignancy; the skin changes come from excess insulin driving skin cell growth via IGF receptors. It’s not a fungal infection of the nails, a retinal vascular disease, or a joint disease—those are different conditions with distinct presentations.

Acanthosis nigricans shows up as symmetric, hyperpigmented, velvety thickening of the skin in folds where skin rubs together, especially the neck, armpits, and groin. This description fits the given choice. It’s commonly tied to insulin resistance and obesity, and in adults it can be a sign of an underlying malignancy; the skin changes come from excess insulin driving skin cell growth via IGF receptors. It’s not a fungal infection of the nails, a retinal vascular disease, or a joint disease—those are different conditions with distinct presentations.