Chondrodermatitis nodularis helicis: a transepidermal perforating disorder.

Chondrodermatitis nodularis helicis is a chronic disorder occurring exclusively on the ear. It is most common in the sixth decade, and two thirds of the patients are men. Although it has no single characteristic histologic feature, a diagnosis can be made with certainty with a clinical history and a combination of morphologic changes seen in the cartilage and overlying skin. The natural history and histology are similar to a group of disorders characterized by transepithelial elimination known as the perforating dermatoses.