**Question:** Crocodile skin appearance is seen in-

A. Acanthosis nigricans
B. Erythema nodosum
C. Kawasaki disease
D. Dermatomyositis

**Correct Answer:** A. Acanthosis nigricans

**Core Concept:**
Acanthosis nigricans is a skin condition characterized by the development of dark, velvety, thickened, and hyperkeratotic lesions, which is often associated with systemic factors such as hormonal imbalances, obesity, or medication intake.

**Why the Correct Answer is Right:**
Acanthosis nigricans is a sign of an underlying systemic disorder, most commonly hormonal imbalances (e.g., insulin resistance in diabetes mellitus) or medications (e.g., contraceptives, growth hormone therapy). The condition is characterized by the hyperkeratotic and hyperpigmented changes in the skin, which give it a "crocodile skin" appearance.

**Why Each Wrong Option is Incorrect:**

A. Erythema nodosum, a dermatological condition, presents with subcutaneous inflammation causing tender, red nodules below the skin surface, not the "crocodile skin" appearance.
C. Kawasaki disease is a systemic vasculitis affecting children, characterized by fever, mucocutaneous changes, and systemic inflammation; it does not present with the "crocodile skin" appearance.
D. Dermatomyositis is a connective tissue disorder characterized by muscle inflammation, muscle weakness, and skin changes; it does not present with the "crocodile skin" appearance.

**Clinical Pearl:**
Acanthosis nigricans should raise suspicion for the underlying systemic disorder, and appropriate investigations should be carried out to identify the cause. Early identification and management of the underlying condition can prevent severe complications.