This fibrinoid change is so characteristic that a diagnosis of 'chondrodermatitis nodularis versus excoriation' can be given based upon a superficial biopsy of an ear with no other clinical history. If there is an erosion or ulcer, the fibrinoid change is seen at the edge of the defect. Fibrinoid change may be relatively superficial, or it may extend in a column as far down as to the cartilage. The epidermis may be intact or eroded. The adjacent epidermis is often acanthotic and may even be pseudoepitheliomatous.
Increased vascularity is common.
Inflammatory infiltrates are variable or may be absent. So-called changes in the cartilage have been overemphasized in the literature. It is quite likely that the apex of the ridge of cartilage acts as a pointed anvil resulting in the cutaneous changes above it. It is not surprising that the lesion may recur if some of the underlying cartilage is not removed. Note the vertical change in the skin above the apex of the cartilage.