Pyoderma Gangrenosum

Updated: Mar 09, 2020
  • Author: J Mark Jackson, MD; Chief Editor: William D James, MD  more...
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Pyoderma gangrenosum is an uncommon, ulcerative cutaneous condition of uncertain etiology. It is associated with systemic diseases in at least 50% of patients who are affected. [1, 2] The diagnosis is made by excluding other causes of similar-appearing cutaneous ulcerations, including infection, malignancy, vasculitis, vasculopathy, venous insufficiency, collagen-vascular diseases, diabetes, and trauma. In a process termed pathergy, new ulcerations may occur after trauma or injury to the skin in 30% of patients who already have pyoderma gangrenosum. (See Presentation, DDx, and Workup.)

Patients with pyoderma gangrenosum may have involvement of other organ systems that manifests as sterile neutrophilic infiltrates. Culture-negative pulmonary infiltrates are the most common extracutaneous manifestation. [3, 4] Other organs systems that may be involved include the heart, the central nervous system, the gastrointestinal (GI) tract, the eyes, [5, 6] the liver, the spleen, the bones, and the lymph nodes. (See Presentation and Workup.)

Therapy for pyoderma gangrenosum involves the use of anti-inflammatory agents, including antibiotics, corticosteroids, immunosuppressive agents, and biologic agents. The prognosis is generally good; however, the disease can recur and residual scarring is common. (See Prognosis, Treatment, and Medication.)


The etiology of pyoderma gangrenosum is poorly understood, but dysregulation of the immune system (specifically, altered neutrophil chemotaxis) is believed to be involved.



Pyoderma gangrenosum occurs in about 1 in 100,000 persons each year in the United States. Although pyoderma gangrenosum affects both sexes, a slight female predominance may exist. [7, 8]

All ages may be affected by the disease, but it predominantly occurs in the fourth and fifth decades of life. Children account for only 3-4% of the total number of cases. (Nothing is clinically distinctive about pyoderma gangrenosum in children and adolescents other than the age of the patients.) [9]



The prognosis of pyoderma gangrenosum is generally good; however, the disease may recur, and residual scarring is common. One study reported that 16% of their 103 patients died during the 8-year study period. [8] Pain is a common complaint of patients and may require pain medication for control.

Most patients with pyoderma gangrenosum improve with initial immunosuppressive therapy and require minimal care afterwards. However, many patients follow a refractory course, and multiple therapies may fail. These patients pose a difficult clinical problem that requires frequent follow-up and long-term care.

Some patients demonstrate pathergy, or the development of pyoderma gangrenosum–like lesions at the site of skin trauma; in such instances, protection of the skin from trauma may prevent a recurrence of the disease. Pathergy may create problems with wound healing, especially after surgical procedures (eg, breast reconstruction, grafting). [10, 11]

Death from pyoderma gangrenosum is rare, but it may occur due to an associated disease or as a result of therapy.