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

## TL;DR

A rare case of bilateral pyoderma gangrenosum in an elderly woman was correctly diagnosed and treated with corticosteroids after initial misdiagnosis as an infection.

## Contribution

Highlights the atypical bilateral presentation of pyoderma gangrenosum and emphasizes the importance of early biopsy and corticosteroid therapy.

## Key findings

- Bilateral pyoderma gangrenosum can occur without systemic disease and mimic infectious or vascular ulcers.
- Skin biopsy confirmed the diagnosis and showed neutrophilic infiltrate with dermal necrosis.
- Treatment with oral prednisolone led to rapid healing and no recurrence.

## Abstract

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
Pseudomonas aeruginosa
. 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.

Bilateral involvement of pyoderma gangrenosum is extremely rare and can easily be misdiagnosed as infection or vascular ulcers. Early biopsy, exclusion of other similar conditions, and rapid initiation of corticosteroid therapy are essential to prevent unnecessary interventions and achieve favorable outcomes.