Table 2.

Improved diagnostic tool for pyoderma gangrenosum

Major criteria

  • Biopsy of ulcer edge demonstrating neutrophilic infiltrate

Minor criteria

  • Exclusion of infection

  • Pathergy

  • History of inflammatory bowel disease or inflammatory arthritis

  • History of papule, pustule or vesicle ulcerating within 4 days of appearing

  • Peripheral erythema, undermining border, and tenderness at ulceration site

  • Multiple ulcerations, at least one on anterior lower leg

  • Cribriform or ‘wrinkled paper’ scar(s) at healed ulcer sites

  • Decreased ulcer size within 1 month of initiating immunosuppressive medication(s)