Pyoderma Gangrenosum Flashcards
What is pyoderma gangrenosum (PG)?
A rare, non-infectious, neutrophilic dermatosis characterized by painful, rapidly progressive ulceration with undermined borders.
What is the hallmark feature of PG?
Painful ulcers with violaceous, undermined edges and purulent bases.
Who is most commonly affected by pyoderma gangrenosum?
Adults aged 20–50 years, with a slight female predominance.
What is the underlying cause of PG?
The exact cause is unknown, but it involves dysregulation of the immune system, specifically neutrophil dysfunction.
What systemic diseases are commonly associated with PG?
Inflammatory bowel disease (Crohn’s disease, ulcerative colitis).
Rheumatologic conditions (e.g., rheumatoid arthritis, seronegative arthritis).
Hematologic diseases (e.g., myelodysplastic syndrome, leukemia).
Monoclonal gammopathies (e.g., IgA gammopathy).
What triggers can precipitate PG?
Trauma or surgery (pathergy phenomenon).
Stress.
Infection or injury.
What is the pathophysiologic mechanism in PG?
Dysregulated immune response with excessive neutrophil infiltration, leading to tissue destruction and ulceration.
What are the characteristic features of pyoderma gangrenosum ulcers?
Painful, rapidly enlarging ulcers.
Undermined, violaceous borders.
Purulent or necrotic bases with granulation tissue.
What is the most common site of PG lesions?
Lower extremities, particularly the anterior tibia.
What are the subtypes of pyoderma gangrenosum?
Ulcerative PG: Classic form with deep ulcers.
Bullous PG: Associated with hematologic malignancies, presents with superficial vesicles or bullae.
Pustular PG: Small pustules, often associated with inflammatory bowel disease.
Vegetative PG: A milder, less aggressive form with superficial, non-painful ulcers.
How is pyoderma gangrenosum diagnosed?
Clinical diagnosis based on characteristic ulcers and exclusion of other causes.
No definitive test; relies on history, examination, and biopsy.
What are key histological features of PG?
Dermal neutrophilic infiltrate without vasculitis.
Ulceration and necrosis.
Exclusion of infection or malignancy.
Why is it important to rule out infection in PG?
Treatment involves immunosuppression, which can worsen an underlying infection.
What are the goals of treatment in PG?
Reduce inflammation, promote ulcer healing, and manage underlying conditions.
What is the first-line treatment for PG?
Systemic corticosteroids (e.g., prednisone) or cyclosporine to suppress the immune response.
