Pyoderma Gangrenosum Mimicking Necrotizing Fasciitis: A Case Report

Area of Science:

• Dermatology
• Immunology

Background:

• Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis with variable clinical presentations.
• PG can be misdiagnosed as infectious or other inflammatory conditions, delaying appropriate treatment.

Observation:

• A 68-year-old woman presented with knee swelling, erythema, papules, and pustules post-fall, initially suspected as necrotizing fasciitis (NF).
• Despite antibiotics and debridement, her condition worsened, with persistent fever and elevated inflammatory markers.
• Histopathology revealed neutrophilic infiltrate, and cultures were negative, supporting a PG diagnosis.

Findings:

• Pustular PG was diagnosed based on abundant pustules and lack of fat necrosis during surgery.
• Oral prednisolone rapidly resolved symptoms, followed by wound therapy, skin grafting, and adalimumab.
• The patient achieved clinical stability without relapse.

Implications:

• Distinguishing PG from NF is crucial due to overlapping presentations and potential for aggressive management.
• Clinical assessment, including evaluation of skin lesions and fat necrosis, is vital for early PG diagnosis.
• Considering PG in atypical presentations of suspected NF can prevent unnecessary surgical interventions and guide timely treatment.