Surgical Management and Diagnostic Incisional Biopsy of Palisaded Neutrophilic Granulomatous Dermatitis (PNGD): A Case Report.

This case report describes a 29-year-old previously healthy male patient who presented to the emergency room with a painful purpuric vesicular rash. The lesions started on the bilateral lower extremities and rapidly spread to his abdomen and bilateral upper extremities. Otherwise, he remained stable without systemic symptoms. The laboratory studies showed hyperglycemia (344 mg/dL) and elevated hemoglobin A1C (10.3%), revealing previously undiagnosed diabetes mellitus. Treatment started with empiric antimicrobial therapy and supportive care, along with a diagnostic skin biopsy performed in the operating room. He was discharged three days later with outpatient follow-up and glycemic counseling. Our discussion explores the rare presentation of palisaded neutrophilic granulomatous dermatitis (PNGD) in a patient without a known autoimmune history. It highlights the role of a surgically obtained skin biopsy for a definitive diagnosis. In particular, this case links undiagnosed diabetes mellitus to the pathogenesis of PNGD. The report concludes that a systemic evaluation is key for granulomatous dermatoses, as managing underlying metabolic dysfunction can significantly improve the disease course and outcome.