An Eschar-like souvenir from a journey to Colombia: Ecthyma gangrenosum as a differential diagnosis of tropical diseases in immunocompromised patients - a case report.

Background: Ecthyma gangrenosum (EG) is a cutaneous infectious disease characterized by eschar-like skin ulcers typically caused by Pseudomonas aeruginosa. Here, we report a case of relapsing EG in a patient who had returned from a trip to Colombia, thus establishing EG as an important differential diagnosis of tropical diseases, and demonstrating that even long-term antibiotic treatment can result in only partial remission of EG.

Case Presentation: A 77-year-old man with underlying chronic lymphocytic leukemia (CLL) on ibrutinib treatment was admitted because of a superinfected mosquito bite on the left ear and multiple partially necrotic skin lesions disseminated all over the entire body five days after returning from a trip to Colombia. The initial clinical suspicion of a tropical disease (leishmaniosis, systemic mycosis, or others) could not be confirmed. During the diagnostic workup, microbiological cultures of the skin biopsies and bronchoalveolar lavage revealed Pseudomonas aeruginosa, leading to a diagnosis of EG. Initial antibiotic treatment resulted in partial remission. However, the patient had to be re-admitted due to a relapse 3-4 weeks after the first episode. Finally, the patient was successfully treated with a combined approach consisting of antibiotics, recurrent surgical incisions, and administration of immunoglobulins.

Conclusions: In conclusion, EG should be considered as a differential diagnosis in immunosuppressed patients presenting with eschar-like skin ulcers. A combined treatment approach seems to be the best choice to achieve clinical cure and avoid relapse.