Rapidly Progressive, Symmetrical, Acute Cutaneous Necrosis of Bilateral Lower Limbs: A Rare Presentation of Polyarteritis Nodosa.

Acute cutaneous necrosis is a rare presentation of polyarteritis nodosa (PAN). In this study, we report a presentation with symmetrical cutaneous necrosis of the lower limbs, which ascended upward at a rapid rate. A 47-year-old man presented with a fever of one day and pain in the feet for six days. He had no history of claudication. Upon examination, he was febrile, and subtle bluish discoloration was observed on the sole of his foot. There was a bilateral stocking-type paresthesia up to the ankle joint. His blood pressure on admission was 210/120 mmHg. Eight hours later, the pain subsided, but a left-sided foot drop was noted along with the paresthesia extending up both feet to approximately 10 cm above the medial malleolus. The feet turned black, and dark discoloration spread rapidly upward over the next 16 hours, and the skin became necrosed. A clinical diagnosis of vasculitis was established, and the patient received IV methylprednisolone at a daily dosage of 1 g for three days, effectively stopping the advancement of necrosis. This was followed by treatment with IV cyclophosphamide. A conclusive diagnosis of PAN was made, and the patient underwent wound debridement. After three months of physiotherapy, a successful skin graft was performed. Prompt identification of the underlying etiology is crucial to prevent the advancement of necrosis and save the limbs. When vasculitis is suspected, ruling out infectious causes is essential before starting early immunosuppressive treatment.