Pyoderma gangrenosum

Background

Subtypes

• Ulcerative: ulceration with rapidly-evolving purulent wound
• Pustular: discrete pustules, sometimes self-limited, and most commonly associated with inflammatory bowel disease
• Bullous: superficial bullae with ulcerations
• Vegetative: erosions with superficial ulcers

Associated Disorders

• Inflammatory bowel disease (40% of cases with a known association), ulcerative colitis more than Crohn disease
• Inflammatory arthritis (20%), particularly seronegative rheumatoid arthritis or spondylitis
• Solid organ malignancy (5-10%)
• Hematologic malignancy (5-10%)
• Other hematologic disorder (5%), including MGUS/myeloma, myelodysplastic syndrome, or polycythemia vera, lymphoma, leukemia
• Rarely, hepatitis C
• Idiopathic in about 50% of cases

Clinical Manifestations

• Chronic wound, most commonly on lower legs in the pretibial area
• Can occur anywhere on the body, particularly at surgical sites
• Rarely, can involve upper airway, eye, genital mucosa, lung (sterile neutrophilic pulmonary infiltrates), splenic infiltrates, myositis, and sterile osteolysis

Diagnosis

Diagnostic Criteria

• Major criterion:
  • Biopsy of ulcer edge demonstrating a neutrophilic infiltrate
• Minor criteria:
  • Exclusion of infection
  • Pathergy
  • Personal history of inflammatory bowel disease or inflammatory arthritis
  • History of papule, pustule, or vesicle that rapidly ulcerated
  • Peripheral erythema, undermining border, and tenderness at site of ulceration
  • Multiple ulcerations (at least one occurring on an anterior lower leg)
  • Cribriform or "wrinkled paper" scar(s) at sites of healed ulcers
  • Decrease in ulcer size within one month of initiating immunosuppressive medications
• Interpretation:
  • Positive if at the major criterion and at least four minor criteria are present

Further Reading

• Pyoderma gangrenosum – a review. Orphanet J Rare Dis 2, 19 (2007). doi: 10.1186/1750-1172-2-19