Pyoderma Gangrenosum as the Initial Presenting Manifestation of Ulcerative Colitis: A Case Report

Abstract

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis frequently associated with inflammatory bowel disease (IBD), particularly ulcerative colitis (UC). Although PG usually occurs during established IBD, it may rarely precede intestinal manifestations, creating a significant diagnostic challenge. We report the case of a 36-year-old woman with no relevant medical history who presented with severe painful ulcero-necrotic skin lesions involving the left wrist and dorsal region, without digestive symptoms. Histopathological examination revealed a dense neutrophilic dermal infiltrate. After extensive exclusion of infectious, vascular, neoplastic and autoimmune causes, the diagnosis of PG was established according to the criteria of Maverakis et al. Systemic corticosteroid therapy was initiated, resulting in progressive healing of the cutaneous lesions. Two months later, the patient developed bloody diarrhoea and abdominal pain. Colonoscopy demonstrated continuous inflammatory lesions compatible with moderately active left-sided UC, and histological examination confirmed the diagnosis. Oral mesalazine was introduced with corticosteroid tapering, leading to a favourable clinical course for both cutaneous and intestinal manifestations. This case highlights PG as a possible initial extraintestinal manifestation of UC, preceding digestive symptoms. The atypical localisation of the lesions and the absence of gastrointestinal complaints at presentation contributed to the diagnostic challenge. Early recognition of PG should prompt systematic screening for underlying IBD, as timely diagnosis may significantly influence therapeutic management and long-term prognosis.