Definition

Pyoderma gangrenosum is an uncommon form of skin ulcers. It usually occurs on the lower legs, but can occur anywhere on the skin.

Side View of Skin Ulcer

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Causes

Pyoderma gangrenosum is thought to be an autoimmune disorder, which means it occurs when the body's immune system attacks its own tissues.

Risk Factors

Pyoderma gangrenosum is more likely to occur in people who have other underlying medical conditions, including:

• Ulcerative colitis
• Crohn's disease
• Chronic active hepatitis
• Rheumatoid arthritis
• Polycythemia vera
• Myeloma
• Behcet's syndrome
• Acute myelogenous leukemia
• Chronic myelogenous leukemia

Ulcerative Colitis

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Symptoms

The chief symptom of pyoderma gangrenosum is painful skin ulcers. These ulcers may begin as small pustules, often as the site of a minor injury, but they can enlarge up to 20 centimeters (or 7.9 inches). The ulcers may have a characteristic purple, rolled or undermined edge.

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. He or she will refer you to a dermatologist, who specializes in conditions of the skin. Pyoderma gangrenosum is diagnosed by its appearance and by ruling out other causes of skin ulceration. Tests may include the following:

• Swabs to test for microorganisms
• Biopsy —removal of a sample of tissue to rule out other causes of the ulcers
• Blood tests

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include:

Prevention

There is no known way to prevent pyoderma gangrenosum, but people who have the condition can reduce the chance of getting new ulcers by avoiding injuring the skin.