Skin, Leukocytoclastic vasculitis

This case represents early leukocytoclastic vasculitis. "Leukocytoclastic vasculitis" (LCV) is not a disease diagnosis per se, but rather a histologic reaction pattern denoting hypersensitivity that can be seen in a variety of diseases. An etiology is not found in at least half of cases. LCV classically presents as palpable purpura, although it may present as urticarial plaques, vesicles, bullae or pustules.

Sections show a dermal peri-vascular inflammatory infiltrate, composed predominantly of neutrophils and lymphocytes. Leukocytoclasia (destruction of neutrophils), plump endothelial cells and erythrocyte extravasation are also observed. Fibrinoid vascular wall necrosis, another feature that can be seen in leukocytoclastic vasculitis is not seen.