[Etiology of ecthyma gangrenosum: four cases]

Ecthyma gangrenosum (EG) starts as an erythematous or purpuric macule, papule or plaque that develops into a haemorrhagic bulla, which becomes a necrotic black sore. EG is usually a cutaneous manifestation of Pseudomonas aeruginosa infection but other microbial agents can be involved.

Four patients (three women and one man, mean age: 36 years) with fever and cutaneous black sores characteristic of EG were hospitalized. Three were cardiac transplant recipients treated with immunosuppressant drugs and one had end-stage acute myeloid leukaemia. All had cutaneous necrotic black sores. Blood cultures isolated in one case P. aeruginosa and Candida albicans. Bacteriological culture of cutaneous swabs from necrotic lesions revealed C. albicans and P. aeruginosa in two cases, respectively. The cutaneous black sores healed with appropriate antimicrobial treatment. Three patients were cured but the patient with leukaemia died despite therapy.

These four cases illustrate the clinical polymorphism of EG and the broad spectrum of aetiologies. While EG is primarily considered a cutaneous manifestation of P. aeruginosa infection, other microbial agents such as C. albicans may be responsible, as in two of our cases.