What type of eczema presents as sharply defined coin-shaped lesions on the skin?

Nummular eczema is characterized by sharply defined, coin-shaped lesions that typically appear on the extremities, particularly the legs and hands. This distinct presentation sets it apart from other types of eczema, which may have different morphological features. The lesions are usually itchy and can sometimes become crusted or weep, but their hallmark is the circular, coin-like shape.

In contrast, atopic eczema often presents with more generalized patches of dermatitis that may not have the clearly delineated borders seen in nummular eczema. Contact dermatitis is usually associated with specific triggers and may present as localized rash in response to allergens or irritants but lacks the classic coin-shaped lesions. Dyshidrotic eczema typically manifests as small, fluid-filled blisters on the palms of the hands and soles of the feet, differing significantly from the coin-shaped lesions seen in nummular eczema. Understanding these distinguishing features helps clarify why nummular eczema is the correct answer to this question.