Abstract
Ecthyma gangrenosum (EG) is a rare cutaneous infection caused by Pseudomonas aeruginosa, typically affecting immunocompromised individuals. We present a 42-year-old female with dermatomyositis and recent MDA-5 antibody positivity who developed acute-onset painful ulcers on her hands, face, elbow, and chest. The patient was immunosuppressed due to medications for a previous liver transplant, including tacrolimus, mycophenolate mofetil, prednisone, and monthly intravenous immunoglobulin. Physical examination revealed shallow ulcers with central eschars and fibrinous material resembling characteristic anti-MDA5 dermatomyositis ulcers. Laboratory findings showed leukopenia, elevated erythrocyte sedimentation rate, and mildly elevated muscle enzymes. Superficial wound and tissue cultures confirmed Pseudomonas aeruginosa infection, establishing the diagnosis of ecthyma gangrenosum. The patient was successfully treated with intravenous cefepime followed by oral ciprofloxacin with complete resolution of the ulcers. This case highlights the importance of considering infectious etiologies in immunocompromised patients even when lesions appear consistent with autoimmune disease manifestations. EG can present without systemic signs of infection, emphasizing the need for prompt microbiological evaluation of suspicious lesions in immunocompromised individuals to ensure appropriate diagnosis and treatment.