This is a reply to # 755,137

Pyoderma gangrenosum

Pyoderma gangrenosum is an uncommon cause of skin ulceration. It may affect any part of the skin, but the lower legs are the most common site. It is thought to be an autoimmune disorder.

Pyoderma gangrenosum usually starts quite suddenly, often at the site of a minor injury. It may start as a small pustule, red bump or blood-blister. The skin then breaks down resulting in an ulcer. The ulcer can deepen and widen rapidly. Characteristically, the edge of the ulcer is purple and undermined as it enlarges. It is usually very painful. Several ulcers may develop at the same time. Untreated, the ulcers may continue to enlarge, persist unchanged or may slowly heal. Treatment is usually successful in arresting the process, but complete healing may take months.

Superficial bullous pyoderma gangrenosum

Typical ulcerated pyoderma gangrenosum

Pyoderma gangrenosum often affects a person with an underlying internal disease such as:

• Inflammatory bowel diseases (ulcerative colitis and Crohn disease)
• Rheumatoid arthritis
• Myeloid blood dyscrasias
• Chronic active hepatitis.
• Wegener granulomatosis
• PAPA syndrome
• Miscellaneous less common associations.