A 13-year-old boy is hospitalized while receiving induction therapy for acute myelogenous leukemia. During a period of profound neutropenia, he develops a fever of 39°C associated with rigors. Blood cultures are taken and he is given broad-spectrum antibiotics. Over the next 48 hours, a tender, erythematous 2 × 2 cm papule develops on his arm, the center of which becomes vesicopustular (Figure 107-1). Blood cultures from the initial febrile period are subsequently positive for Pseudomonas aeruginosa. He is treated with combination therapy including piperacillin/tazobactam and gentamicin for two weeks until neutrophil recovery.
Ecthyma gangrenosum on the arm of this 13-year-old boy with acute myelogenous leukemia. This lesion is at a vesicopustular stage of formation. Blood cultures grew Pseudomonas aeruginosa. (Used with permission from Johanna Goldfarb, MD.)
Ecthyma gangrenosum is an infectious lesion of the skin with a characteristic necrotic center. It is seen predominantly in the immunocompromised patients related to Gram-negative bacteremia, typically Pseudomonas aeruginosa.
Etiology and Pathophysiology
Ecthyma gangrenosum is most commonly associated with disseminated P aeruginosa infection; however, it has also been described with other Gram-negative bacilli and fungi, including Aeromonas hydrophila, Enterobacter, Escherichia coli, Morganella, Serratia marcescens, Stenotrophomonas maltophilia, Aspergillus, Candida, Fusarium, and Mucor.1–3
Necrotizing, hemorrhagic vasculitis is seen on histopathology.
Organisms are often seen, particularly within the medial blood vessel layers.2,4
Lesions begin as erythematous macules with rapid progression to papules (Figure 107-2), then pustules, vesiculopustules (Figure 107-1), or bullae. Some lesions may be more nodular in appearance. Central necrosis and ulceration may develop in the later stages of formation (Figure 107-3).
Ecthyma gangrenosum in the early stage of development. Note the papular lesions surrounding a previous wound in this patient with chemotherapy-induced neutropenia. (Used with permission from Camille Sabella, MD.)
Ecthyma gangrenosum in a 14-year-old girl with acute myelogenous leukemia. Note the necrotic appearing center of the lesion and surrounding erythema. Blood culture from this patient grew Pseudomonas aeruginosa. (Used with permission from Camille Sabella, MD. From Sabella C, Cunningham RJ III. Intensive Review of ...