Pyoderma gangrenosum associated with rheumatoid arthritis mimicking vasculitis

Pyoderma gangrenosum is a rare neutrophilic dermatosis characterized by painful, rapidly progressing necrotic ulcers. Although PG has been reported in association with various autoimmune diseases, its coexistence with rheumatoid arthritis (RA) mimicking vasculitis is uncommon. We present a case report of a 75-year-old female with a longstanding history of RA who developed ulcerative skin lesions that initially presented as vasculitis. She presented with new-onset painful, ulcerative skin lesion on the lower extremity, accompanied by malaise. Physical examination revealed asymmetric, deep necrotic ulcers with undermined borders. Laboratory investigations showed elevated acute phase reactants and negative rheumatoid factor. Skin biopsy demonstrated neutrophilic infiltration, confirming the diagnosis of PG. Further investigations, including imaging studies and vasculitis-specific laboratory tests, were negative, ruling out vasculitis. The patient was managed with systemic corticosteroids and immunosuppressive therapy, resulting in significant improvement of skin lesions. This case highlights the importance of considering PG as a potential differential diagnosis in patients with RA presenting with ulcerative skin lesions resembling vasculitis.