Pyoderma gangrenosum

Pyoderma gangrenosum (pie-oh-DER-muh gang-ruh-NO-sum) is a rare condition that causes large, painful sores (ulcers) to develop on your skin, most often on your legs.

It's not certain what causes pyoderma gangrenosum, but it appears to be a disorder of the immune system. People who have certain underlying conditions, such as inflammatory bowel disease or rheumatoid arthritis, are at higher risk of pyoderma gangrenosum.

Treatment typically includes high doses of corticosteroids, such as prednisone, along with other drugs designed to suppress your immune system. It can take weeks or even months to heal the ulcers associated with pyoderma gangrenosum.

Symptoms Causes Risk factors Complications Prevention

Pyoderma gangrenosum usually starts with a small, red bump on your skin, which may resemble a spider bite. Within days, this bump can develop into a large, painful open sore. The ulcers usually appear on your legs, but may develop anywhere on your body. If you have several ulcers, they may grow and merge into one larger ulcer.

When to see a doctor

Talk to your doctor if you develop unexplained blistering on your skin, an itchy rash or a sore that's slow to heal.

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