Skin & Soft Tissue: Pyoderma Gangrenosum

Pyoderma Gangrenosum

Pathophysiology

  • Definition: A Neutrophilic Dermatosis Causing Skin Inflammation & Ulceration
    • Misnomer – Not Infectious & Not Gangrenous
  • Neutrophil-Predominant Infiltration of the Skin
  • Pathophysiology Not Entirely Certain
  • Primary Factors:
    • Neutrophil Dysfunction
    • Systemic Inflammation
    • Genetic Susceptibility

Associated Conditions

  • More than 50% Have an Underlying Systemic Disease
  • Inflammatory Bowel Disease (30-41%)
  • Inflammatory Arthritis (21-25%)
  • Solid Organ Malignancy (7%)
  • Hematologic Malignancy (6%)
  • Other Hematologic Disorders (5%)

Presentation

  • Inflammatory Papule, Pustule or Nodule
  • Expands Rapidly & Then Erodes/Ulcerates
  • Severe Pain (Not Vegetative)
  • Pathergy – Minor Trauma (Bump/Bruise) Progresses to Skin Lesions
  • May Heal with Atrophic/Cribriform Scars

Subtypes

  • Ulcerative (Classic) – Most Common Subtype
    • Initial Inflammatory Lesion (Papule, Pustule or Nodule)
      • Rapid Peripheral Expansion
    • Central Degeneration & Ulceration
      • Necrotic & Purulent Base with Bluish Edges
  • Bullous (Atypical)
    • Initial Blue-Gray Inflammatory Bullae
    • Rapidly Erode with Superficial Ulceration
  • Pustular
    • Rapid Development of Painful Pustules
    • Surrounded by Erythema
  • Vegetative
    • Superficial, Localized & Solitary Nodule or Ulcer
    • Only Mildly Painful
    • May Have a Verrucous Appearance

Pyoderma Gangrenosum 1

Pyoderma Gangrenosum 2

Sites

  • Most Common Sites:
    • Ulcerative: Lower Extremities & Thorax
    • Bullous: Face & Arms
    • Vegetative: Head & Neck
  • Special Sites:
    • Peristomal Pyoderma Gangrenosum
    • Genital Pyoderma Gangrenosum
    • Extracutaneous Pyoderma Gangrenosum (Lungs, Intestine, Liver, Spleen, etc.)
    • Postoperative Pyoderma Gangrenosum (Surgical Site)

Diagnosis

  • Other Diagnoses Must First Be Excluded
  • Delphi Criteria:
    • Require the Major Criteria & Four Minor Criteria
    • Major Criteria:
      • Biopsy of Ulcer Edge Showing Neutrophilic Infiltration
    • Minor Criteria:
      • Exclusion of Infection
      • Pathergy
      • Personal History of IBD or Inflammatory Arthritis
      • History of Papule, Pustule or Vesicle that Rapidly Ulcerated
      • Peripheral Erythema, Undermining Border & Tenderness at Site of Ulceration
      • Multiple Ulcerations (At Least One on the Anterior Lower Leg)
      • Cribriform or “Wrinkled Paper” Scars
      • Decreased Ulcer Size within One Month of Starting Immunosuppressive Therapy

Treatment

  • Treat Underlying Systemic Disease
  • Immunosuppressive Therapy:
    • Limited Disease: Topical Steroids or Calcineurin Inhibitors (Tacrolimus)
    • Extensive/Rapidly Progressing: Systemic Steroids or Cyclosporine
    • Prevention: May Consider Prophylactic Immunosuppressive Therapy Prior to Other Surgeries (Not Proven)
  • Surgical Debridement
    • Controversial & Done Only with Caution – Can Incite Pathergy
    • Only Debride Clearly Necrotic Tissue
    • Attempt to Limit Surgery to Periods of Good Disease Control
  • Other Therapies:
    • Infliximab (TNF-Alpha Inhibitor)
    • Mycophenolate
    • Methotrexate
    • Azathioprine
    • Intravenous Immunoglobulin (IVIG)

References

  1. Monopol. Wikimedia Commons. (License: CC BY-SA-3.0)
  2. Crohnie. Wikimedia Commons. (License: Public Domain)