Ecthyma gangrenosum caused by Citrobacter freundii

A 55-year-old man undergoing chemotherapy for recurrent multiple myeloma presented with a 2-day history of bilateral lower leg rash with pain and oedema. On examination, there were numerous non-palpable retiform pruritic patches over both lower legs. Skin pnch biopsy demonstrated a diffuse interstitial neutrophilic infiltrate with necrosis. Peripheral blood and skin tissue cultures both isolated Citrobacterfreundii , consistent with a rare form of ecthyma gangrenosum. The patient responded with appropriate antibiotic therapy and removal of medical port. He made a full recovery from this infectious complication of his underlying immunosuppression.