Ecthyma Gangrenosum
A 21-year-old woman with acute myeloid leukemia who was undergoing induction chemotherapy presented with a lesion on her left knee that had developed 5 days after initiation of therapy. A physical examination revealed a 2-cm hemorrhagic patch with an erythematous border (Panel A). The patient was afebrile, and other than the lesion, the findings from physical examination were unremarkable. Laboratory findings were notable for pancytopenia, including an absolute neutrophil count of 490 cells per cubic millimeter (normal range, 950 to 5450). The lesion progressed rapidly into a violaceous pustule (Panel B), and fever (temperature of 39.5°C) subsequently developed in the patient. A punch biopsy of the lesion was performed, and the specimen showed perivascular hemorrhage and infiltration of neutrophilic granulocytes with central necrosis. Blood and wound cultures grew Pseudomonas aeruginosa,and a diagnosis of ecthyma gangrenosum was made. Ecthyma gangrenosum is a cutaneous infection associated with P. aeruginosabacteremia. The infection typically occurs in immunocompromised or critically ill patients and warrants prompt diagnosis and treatment. The patient was treated with ceftazidime and gentamicin, administered intravenously. Because deep infection was suspected, she underwent surgical débridement (Panel C). As the patient recovered from the aplastic phase, the wound healed substantially (Panel D shows the wound approximately 3 months after the initiation of induction chemotherapy). The patient did not have a complete remission of acute myeloid leukemia, and she subsequently underwent allogeneic stem-cell transplantation.
