American Board of Internal Medicine (ABIM) Certification Practice Exam

What is a defining symptom of Pyoderma gangrenosum?

1. Painful pustules that ulcerate rapidly

2. Clean-based ulceration

3. Distal lower extremity swelling

4. Visible vessel bleeding

The correct answer is: Painful pustules that ulcerate rapidly

The defining symptom of Pyoderma gangrenosum is painful pustules that ulcerate rapidly. Pyoderma gangrenosum is characterized by the sudden onset of painful, erythematous nodules or pustules that can rapidly evolve into deep ulcers. These ulcers typically have undermined, ragged borders and are often associated with significant pain. The ulcerations can occur after minor trauma or may develop spontaneously, illustrating an exaggerated inflammatory response. The pain associated with this condition is often more severe than what one would expect from the appearance of the lesions alone, which distinguishes it from other skin conditions. While clean-based ulceration may appear in the context of other ulcerative conditions, it is not a hallmark symptom of Pyoderma gangrenosum, which typically presents with necrotic tissue and undermined edges. Similarly, distal lower extremity swelling is not a defining characteristic, as it might be associated with a variety of conditions that cause swelling but do not specifically indicate pyoderma gangrenosum. Visible vessel bleeding could occur due to the ulcerations but is not a defining symptom of the disorder. Thus, the presence of painful pustules that ulcerate rapidly is what primarily identifies Pyoderma gangrenosum.