he 36-year-old uremic patient presented to the emergency department because of a sudden onset of shaking chills; hypotension and backache began 30 minutes after hemodialysis. The medical personnel of the hemodialysis center reported that the dialyzer was assumed to be contaminated with improperly processed water. He was hypotensive (80/36 mm Hg) and febrile (40.4°C). Physical examination was unremarkable. Vancomycin plus meropenum was administered after blood cultures were obtained. He developed several discrete erosive lesions located over the vermilion lip mucosa with erythematous background 9 hours later (Fig. 1). The skin lesions rapidly became purulent with central necrosis. A Tzanck smear was performed and no evidence of herpes simplex virus-infected keratinocyte was found on light microscopic examination. Maculopapular eruptions were also found in the lower extremities and perianal region within the next 24 hours. Some of the lesions formed a deep ulcer with necrotic base. The blood cultures yielded Pseudomonas aeruginosa, coagulase-negative Staphylococcus, and Aeromonas hydrophila, which were confirmed to be compatible with organisms recovered from the contaminated dialyzer. Wound cultures obtained from the maculopapular eruptions all failed to yield any pathogens. He recovered completely after completion of a 2-week course of antibiotic therapy.Ecthyma gangrenosum (EG) is an early skin manifestation of gram-negative, particularly P. aeruginosa, septicemia in immunocompromised hosts. However, numerous bacteria are also capable of producing EG-like lesions, including A. hydrophila, Aspergillus species, and Candida albicans. 1 The postulated physiopathogenic mechanism of EG is a vasculitis caused directly by bacilli in the vessel wall, by circulating immune complex, by the effect of bacterial exotoxins or endotoxins, or by both. The failure to isolate the organism from the EG lesions could be explained by the involvement of endotoxins or exotoxins. 2,3 EG presents as maculopapular eruptions, hemorrhagic vesicles or bullae, or nodular lesions. In all forms of EG, central necrosis frequently develops, leaving an ulcer with expanding cutaneous infarction. 4 EG is developed exclusively in immunocompromised hosts, such as neutropenic leukemia patients and infants. In our case, the findings of discrete erosive lesions in the lip could resemble HSV infections, but the combination of the highly toxic clinical presentations as well as the rapid evolution of the lesions raised the concern that the lesion could be the earliest manifestation of life-threatening systemic infection and prompted us to initiate empirical antibiotic coverage. When reviewing the literature, we found that EG caused by direct blood stream infection with P. aeruginosa and A. hydrophila in a uremic patient had not been reported before. Innocent-looking macules or papules may be the first manifestation of bacterial or fungal sepsis. Rapid evolutionary skin lesions in a potentially immunocompromised host should have the suspicion of advanced septi...

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