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RMC Bayonet Point

Pyoderma Gangrenosum


A skin ulcer is an open sore in the skin. 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
Skin Ulcer small
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Pyoderma gangrenosum is thought to be caused by a problem with the immune system. The immune system finds and attacks foreign items in the body like viruses. Sometimes the immune system attacks the body's own tissue. In this case, the immune system attacks an area of the skin.

Risk Factors

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


The main symptom of pyoderma gangrenosum is a painful skin ulcer. These ulcers may begin as small-irritated bumps from an injury. However, the ulcer can grow up to 7.9 in (inches) (20 cm [centimeters]). The ulcers often have purple edges that appear worn away.


Your doctor will ask about your symptoms and medical history. A physical exam will be done. You may be referred to a skin specialist. Pyoderma gangrenosum is diagnosed by its appearance. Your doctor will also want to rule out other conditions that can cause skin ulcers.

To look for other factors that could cause ulcers, your doctor may order:

  • Sample of ulcer fluids—to look for infection or items that can cause infection
  • Biopsy —a tissue sample examined under a microscope
  • Blood tests


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


Medications to treat pyoderma gangrenosum include:

  • Oral corticosteroids
  • Immunosuppressants
  • Smaller ulcers may be treated with a topical steroid cream or an injection

You may need other medications to treat any underlying conditions

Preventing New Ulcers

Ulcers often begin at the site of injuries. Take precaution to prevent injuries when possible. Wear proper safety gear and avoid high impact or full contact activities.

See your doctor as soon as you notice a possible ulcer.


There are no current guidelines to prevent pyoderma gangrenosum.

Revision Information

  • American Academy of Dermatology

  • American Autoimmune Related Diseases Association

  • Canadian Dermatology Association

  • Canadian Institute for Health Information

  • Charles CA, Leon A, et al. Etanercept for the treatment of refractory pyoderma gangrenosum: a brief series. Int J Dermatol. 2007 Oct;46(10):1095-1099.

  • Pyoderma gangrenosum. DermNet NZ website. Available at: Accessed December 7, 2012.

  • Pyoderma gangrenosum. EBSCO DynaMed Plus website. Available at: Updated May 24, 2016. Accessed September 27, 2016.

  • Reguiaï Z, Grange F. The role of anti-tumor necrosis factor-alpha therapy in Pyoderma gangrenosum associated with inflammatory bowel disease. Am J Clin Dermatol. 2007;8(2):67-77.