Pyoderma Gangrenosum

Pyoderma gangrenosum (PG) is a rare inflammatory skin condition characterized by painful, necrotic ulcers. This disease is associated with autoimmune mechanisms and frequently coexists with systemic diseases such as inflammatory bowel diseases (Crohn disease and ulcerative colitis), rheumatoid arthritis, and hematologic malignancies like.

PG typically begins as a pustule or nodule and rapidly progresses to necrotic ulcers. Although most commonly affecting the lower extremities, it can occur anywhere on the body. The pathogenesis of PG remains incompletely understood, but it is believed to involve immune dysregulation, neutrophil dysfunction, and genetic factors.

• Incidence: 3–10 cases per 100,000 individuals
• Most commonly occurs between 20 and 50 years of age
• More common in women than in men
• Approximately 50% of patients have associated inflammatory or hematologic disorders

The exact cause of pyoderma gangrenosum is unknown together, but the most widely accepted mechanism is autoimmune-mediated inflammation.

Pyoderma gangrenosum initially presents as an inflammatory pustule or nodule and rapidly evolves into painful, necrotic ulcers with expanding borders.

Main Clinical Forms

• Most common form
• Begins as an erythematous pustule or papule
• Progresses rapidly to irregularly bordered, deep, necrotic ulcers
• Most frequently affects the lower extremities
• Characterized by severe pain and tenderness

• Usually associated with inflammatory bowel disease
• Presents as superficial pustular lesions
• May resolve without progressing to necrotic ulceration

• Most commonly associated with hematologic malignancies
• Features rapidly developing bullous and hemorrhagic lesions
• Face, upper extremities, and trunk are more frequently involved

• Mild course with less frequent association with systemic disease
• Characterized by non-deepening, verrucous (wart-like) lesions

• Ulceration around a stoma (e.g., colostomy or ileostomy site)
• Most commonly seen in patients with inflammatory bowel disease

The diagnosis of pyoderma gangrenosum is made clinically, as there is no specific diagnosis test. However, biopsy and laboratory tests are required to exclude other causes.

• Major Criteria
• • Presence of rapidly progressive, painful, necrotic ulcers
  • Exclusion of other causes
• Minor Criteria (At least two must be present)
• • Pathergy phenomenon
  • Association with systemic disease
  • Neutrophilic inflammation at lesion margins
  • Rapid response to treatment (corticosteroids, immunosuppressants)

• Infectious ulcers (bacterial, viral, fungal)
• Vasculitides (Wegener granulomatosis, PAN)
• Malignant ulcers (cutaneous T-cell lymphoma, SCC)
• Autoimmune bullous diseases (pemphigoid, pemphigus)

Early and aggressive immunosuppression is the cornerstone of pyoderma gangrenosum treatment. Therapy is tailored according to disease severity and underlying conditions.

• Topical corticosteroids (clobetasol propionate 0.05%)
• Topical calcineurin inhibitors (tacrolimus)
• Barrier creams and wound care products

• Corticosteroids:
• • Prednisone 0.5–1 mg/kg/day
  • Dose is tapered upon rapid response
• Immunosuppressive Agents:
• • Cyclosporine
  • Mycophenolate mofetil
  • Methotrexate
  • Azathioprine
• Biologic Therapies (for refractory cases)
• • TNF-α inhibitors (infliximab, adalimumab)
  • IL-1 inhibitors (anakinra)
  • JAK inhibitors (tofacitinib)

• NSAIDs or opioids for pain control
• Antiseptic wound care to prevent infection
• Surgical interventions that may trigger disease flare-ups should be avoided