gangrenosum

Gangrenosum is not a widely used standalone medical term. In medical literature, it is most often used to refer to ecthyma gangrenosum, a rapidly progressing necrotic cutaneous lesion typically associated with Pseudomonas aeruginosa bacteremia. It most often affects immunocompromised individuals, such as those with neutropenia, hematologic malignancies, diabetes, burns, or critical illness, and it reflects underlying sepsis and vascular injury rather than a primary skin disease.

Clinically, ecthyma gangrenosum presents as rapidly evolving skin lesions. Early lesions are painless erythematous or violaceous macules that quickly become hemorrhagic vesicles or bullae and then necrotic ulcers with a central black eschar. Lesions commonly occur on the buttocks, perineum, and limbs, but can appear anywhere. Patients often have fever and signs of systemic infection or sepsis.

Pathophysiology involves invasion of the vascular walls by Pseudomonas aeruginosa with ensuing vasculitis and ischemic necrosis of the overlying skin. The condition is more aggressive in neutropenic or severely immunocompromised patients, where inflammatory responses are blunted and tissue damage progresses rapidly.

Diagnosis relies on clinical suspicion in a septic patient with compatible skin lesions, supported by microbiological cultures. Blood cultures frequently yield Pseudomonas, and culture of lesion material confirms the organism. Histology can show necrotizing vasculitis with bacterial invasion.

Management requires prompt, broad-spectrum anti-pseudomonal antibiotics, adjusted to culture results, and source control of infection. Supportive care for sepsis is essential. Prognosis varies and is historically guarded due to the association with disseminated infection and immunosuppression; early recognition and treatment improve outcomes.