Cutaneous leukocytoclastic vasculitis. Serial histopathologic evaluation demonstrates the dynamic nature of the...

Data from experimentally induced cutaneous vasculitis have suggested that the inflammatory infiltrate is dynamic. In contrast, data from humans with cutaneous vasculitis have suggested that two distinct patterns of cellular infiltrate exist, a mononuclear-predominant and a neutrophilic-predominant type. There are little data regarding the temporal evolution of spontaneously occurring cutaneous vasculitis in humans. A patient with a cutaneous leukocytoclastic vasculitis manifest as palpable purpura had four lesions encircled on the day of presentation. Biopsies of these lesions were obtained sequentially at 0, 24, 48, and 120 hours. The histopathologic specimens were graded without knowledge of the timing of the biopsy. The character of the infiltrate progressively changed from a neutrophilic-predominant to a mononuclear-predominant infiltrate supporting the theory of a dynamic process in cutaneous vasculitis. The previous reports that suggest that there are two distinct inflammatory cell types may be the result of performing the biopsy at one point in time during this transitory process.