**Question:** Coin shaped eczema is –

A. Erythema multiforme
B. Dermatitis herpetiformis
C. Behçet's disease
D. Morphea

**Correct Answer:** D. Morphea

**Core Concept:** Coin shaped eczema refers to a specific clinical presentation in dermatology that can be associated with various dermatological conditions. In this context, we are primarily discussing a type of scleroderma called Morphea, also known as localized scleroderma. Morphea is a group of rare, benign connective tissue disorders characterized by abnormal collagen deposition and inflammation in the dermis and/or subcutaneous tissue.

**Why the Correct Answer is Right:** Morphea presents as a skin condition characterized by hyperpigmentation, induration, and ulceration, often forming a round, coin-like lesion. This clinical appearance aligns with the coin shaped eczema described in the question. The condition primarily affects children and young adults, and it can be classified into five subtypes: circumscribed scleroderma, linear scleroderma, scleroderma profundus, scleroderma circumscriptum, and scleroderma areola.

**Why Each Wrong Option is Incorrect:**

A. Erythema multiforme is a group of skin disorders characterized by symmetric, targetoid lesions primarily affecting the extremities and mucous membranes. It is not coin shaped and is not a subtype of scleroderma.

B. Dermatitis herpetiformis is a chronic, immune-mediated inflammatory skin condition related to coeliac disease. It presents with papules, pustules, and vesicles, not the coin-like appearance described in the question.

C. Behçet's disease is an autoinflammatory disorder associated with oral ulcers, genital ulcers, uveitis, and arthralgia. It is not coin shaped and is not a subtype of scleroderma.

**Clinical Pearl:** Coin shaped eczema is an important clinical clue in diagnosing Morphea. Although coin shaped eczema can be confused with other conditions like lichen planus, it is crucial to distinguish between them based on the dermatological appearance. A detailed dermatological examination and systemic evaluation are necessary for an accurate diagnosis and appropriate management of these conditions.