Bilateral Idiopathic Pyoderma Gangrenosum: A Case Report of an Atypical Presentation

Pyoderma gangrenosum (PG) is a rare non-infectious neutrophilic dermatosis which is characterized by a rapidly progressive, painful ulcer. Bilateral manifestation of PG is exceptionally rare and can easily be misdiagnosed as infection or vascular ulceration, delaying proper treatment. A 76-year-old woman presented with painful, crusted ulcers on her bilateral lower legs that developed over 2 weeks. Initially, the lesions erupted as erythematous papules that enlarged rapidly and ulcerated. There was no history of trauma, systemic illness, or prior ulceration. Laboratory tests revealed mild anemia and an elevated C-reactive protein level. Swab culture from the wound site showed growth of <i>Pseudomonas aeruginosa</i>. There was no response to antibiotics, suggesting a non-infective etiology. An incisional skin biopsy revealed dense neutrophilic infiltrate with dermal necrosis in the absence of vasculitis or infection, findings characteristic of neutrophilic dermatosis and consistent with PG. The patient was treated with oral prednisolone and local saline dressings, resulting in significant improvement within 2 weeks and complete healing without recurrence. PG can occur even in the absence of systemic diseases and may mimic infectious or vascular ulcers. Awareness about atypical presentations, early biopsy and timely initiation of corticosteroid therapy is essential to avoid misdiagnosis and achieve favorable outcomes.