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Pyoderma Gangrenosum

  • Amy Scholten, MPH
Publication Type:


Pyoderma Gangrenosum


Pyoderma gangrenosum is a rare form of open sores (ulcers) on the skin. The sores often occur on the lower legs. However, they can happen anywhere on the skin.

Side View of Skin Ulcer.

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The exact cause of pyoderma gangrenosum is not known. It may be caused by the immune system attacking a place on the skin.

Risk Factors

This problem is more common in women and people 20 to 60 years of age. The risk is higher in those who have:


The main symptom of pyoderma gangrenosum is a painful skin sore. Sores may begin as small bumps from an injury. However, a sore can grow up to 7.9 in (inches) (20 cm [centimeters]). The sores often have purple edges that look worn.


The doctor will ask about symptoms and health history. A physical exam will be done. A doctor who focuses on skin problems may need to be seen. Pyoderma gangrenosum may be diagnosed by how it looks.

The doctor may want to rule out other causes of the skin sores. Tests may be done, such as:

  • Sample of fluids from the sores—to look for infection or causes of infection
  • Biopsy—a tissue sample to be tested
  • Blood tests


The goals of treatment are to help sores heal and prevent further problems. Underlying conditions may also need to be treated. Options may be:

  • Medicines to help heal sores, such as:
    • Corticosteroid pills—to reduce swelling
    • Steroid cream or an injection—for smaller sores
  • Immunosuppressants—to stop the immune system from attacking the skin

Other medicines may be given to treat underlying conditions.

Surgical skin grafts may be done if other treatments do not work.


There are no current guidelines to prevent pyoderma gangrenosum.





  • Alavi, A., French, L.E., et al. Pyoderma gangrenosum: an update on pathophysiology, diagnosis and treatment. Am J Clin Dermatol, 2017; 18 (3): 355-372.
  • Pyoderma gangrenosum. DermNet New Zealand website. Available at: https://www.dermnetnz.org/topics/pyoderma-gangrenosum.
  • Pyoderma gangrenosum. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/pyoderma-gangrenosum.


  • Marcin Chwistek, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.