Shanghai Fever in Early Childhood: Lessons From Two Fatal Cases

To the Editors: Shanghai fever is a rare syndrome defined as community-acquired Pseudomonas aeruginosa sepsis of enteric origin, fulminant clinical progression, gastrointestinal involvement, necrotizing skin lesions and high case-fatality rates even among previously healthy children.1–3 We describe two fatal cases in infants, emphasizing key clinical features and the importance of early recognition. Case 1. A 16-month-old boy presented with fever and abdominal pain, which progressed to perianal erythema, edema and rectal prolapse. On admission, he was critically ill with marked abdominal distension, severe neutropenia, coagulopathy, hypoalbuminemia and metabolic acidosis. Empirical cefepime plus metronidazole was initiated. Within 48 hours, ecthyma gangrenosum developed, with diarrhea and worsening abdominal distension (Fig. 1). Computed tomography revealed diffuse rectoanal wall thickening, and laparotomy showed stenosis with ischemic inflammation, requiring colostomy. Despite antimicrobial escalation and clearance of bacteremia, necrosis worsened. Multidrug-susceptible P. aeruginosa was repeatedly isolated, and the patient died of refractory septic shock on day 15.FIGURE 1.: Ulcerative necrotizing skin lesions on the face and thigh (A, B), suggestive of ecthyma gangrenosum. Perineal erythema and edema associated with rectal prolapse (C). Necrotic perianal lesions (after colostomy) and swollen scrotum (D).Case 2. An 11-month-old girl presented after 4 days of cough, rhinorrhea and fever progressing to lethargy, diarrhea and respiratory distress. She was acutely ill with anemia, leukopenia, thrombocytopenia, coagulopathy, metabolic acidosis and hypoalbuminemia. Empirical ceftriaxone was started. Chest radiography showed bilateral opacities and effusions; and echocardiography revealed severe myocardial dysfunction with ejection fraction of 9%. Despite mechanical ventilation, venoarterial extracorporeal membrane oxygenation and broadened antimicrobial therapy (meropenem, vancomycin, clindamycin), she developed refractory septic shock. Blood culture obtained at admission yielded multidrug-susceptible P. aeruginosa. She died 32 hours after hospital admission. These cases highlight consistent clinical hallmarks: acute febrile illness, gastrointestinal or systemic onset, ecthyma gangrenosum, neutropenia and fulminant sepsis. Importantly, both children died despite isolates being susceptible to commonly used antibiotics, underscoring that virulence factors, rather than resistance, drive the severity of Shanghai fever.2,3 The syndrome remains a diagnostic challenge. In some cases, diarrhea is absent or minimal, which may delay suspicion of an enteric source. Recognition of ecthyma gangrenosum in an otherwise healthy child should prompt immediate consideration of P. aeruginosa sepsis and urgent initiation of directed therapy. Early suspicion is critical, as survival is closely linked to the timely administration of appropriate antimicrobials and aggressive supportive care.1,4 Beyond the clinical features, these cases emphasize broader lessons from the pandemic era. First, the importance of maintaining strong microbiologic surveillance to detect rare but severe pathogens in community settings. Second, the necessity of clear communication strategies with caregivers and frontline clinicians, as misperceptions of P. aeruginosa as a “hospital-acquired” pathogen may delay recognition of community-acquired infections. Finally, they remind us that community-acquired pediatric sepsis remains a heterogeneous and challenging entity, where pathogens can produce devastating outcomes even in the absence of underlying conditions. In conclusion, Shanghai fever should be suspected in infants presenting with fever, gastrointestinal or systemic symptoms, sepsis and ecthyma gangrenosum, even when previously healthy.1,4,5 Awareness of its hallmark signs and recognition that susceptibility testing does not predict clinical evolution are crucial to improve outcomes. Pediatricians should remain vigilant for this rare but devastating disease.