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Pyoderma gangrenosum

Last updated: April 28, 2025

Summarytoggle arrow icon

Pyoderma gangrenosum is an inflammatory skin condition characterized by one or more rapidly progressive, painful skin ulcers with neutrophilic infiltration. Pyoderma gangrenosum is likely due to autoimmune dysregulation and is associated with autoimmune conditions such as inflammatory bowel disease (IBD) and rheumatoid arthritis. Pyoderma gangrenosum may be precipitated by trauma, often developing as a result of pathergy. Diagnosis is often based on clinical suspicion and can be confirmed with skin biopsy. Treatment includes supportive care, immunosuppressants, and monitoring.

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Epidemiologytoggle arrow icon

  • Prevalence: 58 cases per million adults in the US [1]
  • Worldwide incidence: ∼ 3–10 cases per million per year [2]
  • Most often manifests in individuals ∼ 50 years of age but can occur between 20–60 years of age or older [1][3]
  • > [3]
  • Often associated with a higher mortality rate than similar groups of the same age [1]

Epidemiological data refers to the US, unless otherwise specified.

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Etiologytoggle arrow icon

Pyoderma gangrenosum is likely due to autoimmune dysregulation and may be idiopathic or associated with systemic autoimmune conditions. [2]

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Clinical featurestoggle arrow icon

Distinguishing features

  • Skin lesions [1][2][3]
  • Distribution [3]
    • Frequently extensor surfaces of lower legs
    • Other possible sites: head, neck, trunk, fingers, vulva, peristomal skin

Disease severity [1][2]

The severity of pyoderma gangrenosum can be classified based on ulcer size, number, and/or distribution. [4]

  • Mild disease
    • Ulcer size ≤ 3 cm
    • ≤ 3 lesions
    • ≤ 5% total body surface area
  • Moderate to severe disease
    • Ulcer size > 3 cm
    • > 3 lesions
    • > 5% total body surface area
    • Involvement of the face or genitals
    • Visibility of tendon, bone, and/or muscle
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Diagnosistoggle arrow icon

Consult a specialist (e.g., dermatology) early to avoid diagnostic delay and misdiagnosis, as there are no standardized diagnostic criteria.

Skin biopsy [1][3]

  • Indication: all patients with suspected pyoderma gangrenosum
  • Site: preferably taken from the edge of the ulcer
  • Histological findings (nonspecific)
    • Neutrophilic infiltration (common) and/or lymphocytic infiltration
    • Dermal edema
    • Bacterial and fungal staining to rule out infection

Biopsy findings alone cannot confirm the diagnosis of pyoderma gangrenosum.

Routine laboratory studies [3]

Additional studies [1][3]

Perform age-appropriate cancer screening for all patients and consider the following studies based on clinical suspicion.

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Differential diagnosestoggle arrow icon

The differential diagnoses listed here are not exhaustive.

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Treatmenttoggle arrow icon

Treatment is largely based on expert opinion as there have been few large-scale clinical trials on pyoderma gangrenosum.

General principles

  • All patients
    • Consult dermatology for treatment guidance.
    • Provide supportive care.
    • Manage concurrent associated conditions (e.g., IBD, rheumatoid arthritis) if present.
  • Mild disease: Start topical or intralesional therapy with or without prednisone. [2]
  • Moderate to severe disease: Start prednisone and/or cyclosporine. [2]
  • Monitoring
    • Reassess after 1–3 weeks or longer for response. [1][2]
    • Add additional immunosuppressive therapy if the lesion does not resolve with subsequent reassessments.
    • Consider either tapering off therapy or providing long-term maintenance in patients with complete resolution.

Pharmacological treatment [1][2]

The size and appearance of the ulcer should be well-documented before starting pharmacological treatment since immunosuppression can alter the characteristic appearance of pyoderma gangrenosum ulcers. [1]

Supportive care [1]

Avoid debriding the wound as this can exacerbate the ulcer.

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