Pyoderma gangraenosum

Last Updated: 2023-07-07

Author(s): Anzengruber F., Navarini A.

ICD11: EB21

Brocq, 1916; Brunsting u. Goeckermann, 1930

PG, ulcerative dermatitis, Meleney ulcer, pyodermia vegetans et ulcerans gangraenosa

  • Rare, sometimes painful and destructive, sterile, inflammatory dermatosis associated with abscesses and necrosis
  • It is chronically progressive and resistant to common ulcer therapy

  • Rare condition
  • Slight female predilection
  • Mostly between the ages of 25 and 54
  • Smoking can increase the risk for PG

  • Ulcerative form (classic and most common type): rapidly deep- or area-progressive, purulent-serous ulceration with undermined, livid-red margins. Associated arthritides, inflammatory bowel disease, monoclonal gammopathies  
  • Pustular form: 0.2-0.8 cm pustules, often associated with larger inflammatory plaque(s). Commonly associated inflammatory bowel disease
  • Bullous form: Subepidermal blistering with inflammatory rim that erodes or ulcerates. 
  • Vegetative superficial granulomatous form: superficial mostly solitary ulcer without undermined rim, often in surgical scars.
  • Peristomal form: Ulcerating, painful  papules or plaques around stomas. Further development into the typical ulcerative form with undermined margins.
  • Mucosal type = pyostomatitis vegetans: this very rare, chronic ulcerative clinical picture of the  oral mucosa is considered by some authors to be a (mucosal) variant of pyoderma gangraenosum.

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  • Exact genesis unclear, discussed are abnormal function of neutrophil granulocytes, dysregulation of the immune system, genetic predisposition
  • Frequent association (> 50%) with systemic diseases: e.g. chronic inflammatory bowel diseases, rheumatoid arthritis, haematological diseases or malignancies

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  • Very painful focal skin lesions, often initially consisting of blisters, papules and pustules
  • Pathergy: Often develops after minor trauma (insect bites, small injuries)
  • During progression, deep ulcers develop across the dermis with central necrosis
  • Continuous progression, centrifugal spread
  • Typical: Wall-like, undermined, very painful deep red marginal zone
  • Smudgy, spongy consistency.

  • There are no universal diagnostic criteria, however in JAMA Derm 2018 Maverakis et al published a Delphi consensus (cited verbatim): 
    • Major criterion: Biopsy of ulcer edge demonstrating neutrophils
    • Minor critera (4 of 8): no infection; pathergy; IBD/Arthritis; papule/pustule/vesicle ulcerating within 4 days after appearance; peripheral erythema, undermined border, tenderness at ulceration site; multiple ulcerations including 1 on anterior lower leg; cribriform or wrinkles scar at healed sites; ulcer decreases size after 1 month of immunosuppressives. 
  • History of present illness
  • Clinical features
  • Lab:
    • mildly elevated inflammatory parameters
    • mild anaemia
    • negative ANAs, cANCAs 

Predilection sites: Extensor sides of the lower extremities, even though these are also the site of most other differentials! 

  • Nonspecific histology
  • Dermal abscesses of polymorphonuclear neutrophils
  • Later transition to a mixed cell infiltrate including plasma cells, accompanied by oedema of the papillary dermis, necrosis

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Needless debridement by surgeons when diagnosis is delayed.

Not possible before diagnosis, after diagnosis immunosuppressives should be used until the tendency to form larger ulcers has ceased. 

  • Chronic, progressive course
  • Frequent recurrences
  • Spontaneous healing rather rare

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  2. Powell FC, Schroeter AL, Perry HO, Su WP. Direct immunofluorescence in pyoderma gangrenosum. Br J Dermatol. 1983;108:287–93
  3. Hughes AP, Jackson JM, Callen JP. Clinical features and treatment of peristomal pyoderma gangrenosum. J Am Med Assoc. 2000;484:1546–8.
  4. Von den Driesch P. Pyoderma gangrenosum: A report of 44 cases with follow- up. Br J Dermatol. 1997;137:1000–5
  5. Jacob SE, Weisman RS, Kerdel FA. Pyoderma gangrenosum: Rebel without cure. Int J Dermatol. 2008;47:192–4.
  6. Gameiro A, Pereira N, Cardoso JC, et al. Pyoderma gangrenosum: challenges and solutions. Clin Cosmet Investig Dermatol 2015;8:285–93.
  7. Holland SM. Chronic granulomatous disease. Clin Rev Allergy Immunol 2010;38:3–10.
  8. Bellak JM, Bell MC, Durrani SR, et al. Classical pyoderma gangrenosum associated with abnormal neutrophil oxidative burst. J Allergy Clin Immunol 2012;129:AB159.doi:10.1016/j.jaci.2011.12.358.