A peculiar in situ case of cutaneous leukocytoclastic vasculitis induced by urinary infection

Cutaneous leukocytoclastic vasculitis (LCV) is a disease thought to be related to the presence of immune complex deposition within small blood vessel walls. A 58-year-old female presented with purpuric papules on both legs, occurring concurrent with urinary symptoms. Histologically, an intraepidermal blister with luminal fragmented neutrophils was present. A dermal infiltrate was observed surrounding blood vessels; mild perivascular leukocytoclastic debris favored a diagnosis of LCV. Both direct immunofluorescence and immunohistochemistry staining also favored a diagnosis of LCV. Reactivity of the involved vessels was observed to multiple antibodies and complement, with overexpression of von Willebrand factor, CD15, and CD45. The ribosomal protein Phospho-S6 was also detected within the involved vessels, and on the blister roof and floor. The clinical triggering factor was a urinary infection that had progressed to urosepsis; the symptoms were effectively treated. We present an unusual case, where multiple immune reactions correlate with clinical and histologic changes characteristic of LCV.