Pyoderma Gangrenosum

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PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

See also: Localised Scleroderma (Morphoea) written for patients

Pyoderma gangrenosum (PG) is a rare and serious skin disease in which a painful nodule or pustule breaks down to form a progressively enlarging ulcer. The name relates to the appearance of the ulcers, which have a purulent surface ('pyoderma') and a blue-black edge ('gangrenosum'). However, there is neither infection nor gangrene involved.

There may be an underlying disorder, such as ulcerative colitis, Crohn's disease,rheumatoid arthritis, haematological malignancies, chronic active hepatitis or gammopathy.

PG comes under the heading of neutrophil dermatoses. In these conditions, affected tissue contains a high concentration of neutrophils. Other neutrophil dermatoses include Sweet's syndrome (acute febrile neutrophilic dermatosis), Behcet's disease, neutrophilic dermatosis of the hands and erythema elevatum diutinum.

PG is uncommon. Incidence is estimated to be around 3-10 cases per million population per year worldwide.[1] A UK study estimated incidence rate to be around 0.91 per 100,000 person-years.[2] It may occur at any age, but the peak incidence is over the age of 50, with a slight female preponderance.

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The cause is unknown. 50-70% of cases are associated with other diseases, mainly inflammatory bowel disease (IBD), arthritis and lymphoproliferative disorders.[1] PG may occur in sites of trauma; this phenomenon is called pathergy. It often begins in sites of minor injury (reported in 20-30% of cases).

Associated conditions are:[3][4]

  • IBD - Crohn's disease and more frequently ulcerative colitis:
    • About 2% of IBD patients develop PG.
    • About 30% of PG patients have (or will develop) IBD.
  • Arthritis:
    • Usually seropositive rheumatoid arthritis.
    • Can occur with Behçet's disease, seronegative arthritis and spondyloarthropathy.
  • Liver disease - chronic active hepatitis, hepatitis C and primary biliary cirrhosis.
  • Myeloproliferative disorders - eg, leukaemia, myeloma, lymphoma, monoclonal gammopathies.
  • Pyogenic sterile arthritis, pyoderma gangrenosum and acne syndrome (PAPA syndrome).[5] 
  • Other conditions - also reported with paroxysmal nocturnal haemoglobinuria, systemic lupus erythematosus, antiphospholipid syndrome, vasculitis and Wegener's granulomatosis.[6] 

The occurrence of PG does not seem to relate to the disease activity in conditions such as IBD and arthritis.

Possible precipitating factors for PG are:[3][7]

  • Biopsies, intradermal skin testing, injections, insect bites, etc (due to pathergy).
  • Surgery.
  • Certain drugs - propylthiouracil, the granulocyte colony-stimulating factor pegfilgastrim, isotretinoin and gefitinib.

PG can present in various ways and there are several different forms (listed below). It is not always easy to recognise, although early recognition and treatment are important.

  • Consider PG in any non-healing ulcer or wound.
  • Lesions can progress rapidly, from pimple to crater within 48 hours.

Classical PG

  • This is the most common type.
  • This begins as pustule(s) or nodule(s); these soon break down to form a rapidly enlarging ulcer, which has a raised inflammatory border and a boggy, necrotic base. The base may be studded with small abscesses. The ulcer is usually painful and the pain may be severe. It heals with scarring.
  • The ulcers are most common on the lower legs and trunk.
  • Pathergy (ulcers in the site of minor trauma) is common.
  • The clinical course may follow two patterns:
    • Explosive onset and rapid spread of lesions, with pain, systemic illness and fever.
    • Indolent and slow-spreading, with spontaneous regression and healing in one area and progression in another.

Peristomal PG

  • PG can occur in skin around stoma sites.
  • This is particularly common in IBD patients.
  • Around 15% of all cases of PG.

Vegetative PG

  • This is usually a single lesion in healthy patients; it is a less aggressive form than classical PG. Often there is no systemic disease. It may respond well to topical treatment.
  • Lesions are mainly on the head and neck.
  • The ulceration is more superficial than classical PG; the ulcer base is usually non-purulent, and there are no undermined borders or surrounding erythema.

Bullous PG

  • Presents with concentric, painful bullous areas, rapidly spreading. These break down to form ulcers, which are more superficial than in classical PG. It affects the face and upper limbs more than the legs.
  • It has been reported in association with haematological disease.

Pustular PG

  • There are multiple sterile pustules surrounded by an erythematous halo and associated with fever and arthralgias.
  • It often improves with treatment of the underlying IBD.

Genital PG

  • Typical PG ulcers located on the vulva, penis or scrotum.
  • Behçet's disease should be considered as a differential diagnosis.

Extracutaneous neutrophilic disease

  • Sterile neutrophilic infiltrates - usually in the lungs, but can also occur in the heart, central nervous system, gastrointestinal tract, eye, liver, spleen and lymph nodes.
  • Symptoms reflect the location of the lesions.
  • Oral involvement has also been reported.[8] 

The diagnosis is clinical, and a diagnosis of exclusion. Investigations are needed to exclude other conditions and look for associated disease. Infection, vascular disorders and malignancies in particular need to be excluded.

  • Blood tests:
    • FBC, inflammatory markers, LFTs, urine protein and rheumatological investigations may be appropriate to look for associated diseases (as under 'Aetiology', above).
    • Autoantibodies - patients with PG are often p-ANCA (perinuclear) positive, particularly if inflammatory bowel disease is present. The presence of c-ANCA (cytoplasmic) may indicate Wegener's granulomatosis.
  • Swabs and cultures of the ulcer.
  • Biopsy of the lesion - often indicated to exclude other causes, although there are no specific diagnostic features of PG. Biopsy may sometimes cause extension of the ulcer.

General points

  • Refer urgently to a dermatologist for diagnosis and treatment.
  • Immunosuppression and wound care are the main treatments.
  • There are few controlled trials.
  • Treating any associated disease may help.

Topical and local treatments

  • Wound care - 'moist wound management' is important, using dressings such as foam, laminate, alginate or wet compresses.
  • Potent topical steroids (usually triamcinolone injected into the edge of the ulcer).
  • Other possible treatments include topical tacrolimus, benzoyl peroxide, potassium iodide, nicotine and 5-aminosalicylic acid.[9] Maggot therapy for the wound was used in one case.[10]

Systemic treatments

  • Corticosteroids:
    • These are predictable and effective when delivered in sufficiently high doses. They halt progression and prevent new lesions. High doses (60-200 mg/day) of prednisolone may be needed initially. Pulse therapy using intravenous (IV) methylprednisolone (eg, 1 g/day for 3-5 days) is used in some departments.
  • Sulfa drugs: dapsone, sulfapyridine, and sulfasalazine.
  • Immunosuppressant drugs: ciclosporin is used most commonly when steroids fail or are contra-indicated or not tolerated. Other immunosuppressants used are azathioprine, cyclophosphamide, tacrolimus, mycophenolate mofetil, 6-mercaptopurine, methotrexate and chlorambucil.
  • Biological therapies (anti-tumour necrosis factor alpha treatments):[11] 
    • Infliximab - some success reported in trials.[12]; used in some departments.[4]
    • Etanercept - successful in a handful of single case reports.[13]
    • Adalimumab.[14]
  • Other treatments used are:[15] 
    • Low-dose colchicine.
    • Minocycline.
    • IV immunoglobulin.[16] 
    • Clofazimine.
    • Plasmapheresis.
    • Heparin.
    • Hyperbaric oxygen therapy.[17]
    • Alefacept.[18]


    • Can trigger PG, so used with immunosuppression when in a stage of remission.
    • Skin grafts or bioengineered skin may be used.
  • Pain, wound odour and debility.
  • Scarring of healed lesions.
  • Secondary infection.
  • Involvement of other organs: extracutaneous neutrophilic disease (as above); eye involvement is a rare complication.[19]
  • The clinical course is variable and difficult to predict. There may be spontaneous resolution, a quiescent phase for months or years or flare-ups following minimal trauma or for no apparent cause.
  • Any underlying disease significantly affects the prognosis.[1] 
  • Male sex, older age, bullous variety and association with haematological malignancy are associated with poorer prognosis.
  • A UK-based study found that people with PG had a three times higher risk of death than the general population.[2] 

Further reading & references

  1. Cozzani E, Gasparini G, Parodi A; Pyoderma gangrenosum: a systematic review. G Ital Dermatol Venereol. 2014 Oct;149(5):587-600.
  2. Langan SM, Groves RW, Card TR, et al; Incidence, mortality, and disease associations of pyoderma gangrenosum in the United Kingdom: a retrospective cohort study. J Invest Dermatol. 2012 Sep;132(9):2166-70. doi: 10.1038/jid.2012.130. Epub 2012 Apr 26.
  3. Ruocco E, Sangiuliano S, Gravina AG, et al; Pyoderma gangrenosum: an updated review. J Eur Acad Dermatol Venereol. 2009 Sep;23(9):1008-17. Epub 2009 Mar 11.
  4. Brooklyn T, Dunnill G, Probert C; Diagnosis and treatment of pyoderma gangrenosum. BMJ. 2006 Jul 22;333(7560):181-4.
  5. Pyoderma granulosum; DermNet NZ
  6. Gonzalez-Moreno J, Ruiz-Ruigomez M, Callejas Rubio JL, et al; Pyoderma gangrenosum and systemic lupus erythematosus: a report of five cases and review of the literature. Lupus. 2015 Feb;24(2):130-7. doi: 10.1177/0961203314550227. Epub 2014 Sep 8.
  7. Wollina U; Pyoderma gangrenosum--a review. Orphanet J Rare Dis. 2007 Apr 15;2:19.
  8. Paramkusam G, Meduri V, Gangeshetty N; Pyoderma gangrenosum with oral involvement - case report and review of the Int J Oral Sci. 2010 Jun;2(2):111-6.
  9. Marzano AV, Trevisan V, Lazzari R, et al; Topical tacrolimus for the treatment of localized, idiopathic, newly diagnosed pyoderma gangrenosum. J Dermatolog Treat. 2010 May;21(3):140-3. doi: 10.3109/09546630903268239.
  10. Hunter S, Langemo D, Thompson P, et al; Maggot therapy for wound management. Adv Skin Wound Care. 2009 Jan;22(1):25-7.
  11. Agarwal A, Andrews JM; Systematic review: IBD-associated pyoderma gangrenosum in the biologic era, the response to therapy. Aliment Pharmacol Ther. 2013 Sep;38(6):563-72. doi: 10.1111/apt.12431. Epub 2013 Aug 5.
  12. Brooklyn TN, Dunnill MG, Shetty A, et al; Infliximab for the treatment of pyoderma gangrenosum: a randomised, double blind, placebo controlled trial.; Gut. 2006 Apr;55(4):505-9. Epub 2005 Sep 27.
  13. Rogge FJ, Pacifico M, Kang N; Treatment of pyoderma gangrenosum with the anti-TNFalpha drug - Etanercept. J Plast Reconstr Aesthet Surg. 2008;61(4):431-3. Epub 2007 Jan 23.
  14. Traczewski P, Rudnicka L; Adalimumab in dermatology. Br J Clin Pharmacol. 2008 Nov;66(5):618-25. Epub 2008 Jul 11.
  15. Cohen PR; Neutrophilic dermatoses: a review of current treatment options. Am J Clin Dermatol. 2009;10(5):301-12. doi: 10.2165/11310730-000000000-00000.
  16. Cummins DL, Anhalt GJ, Monahan T, et al; Treatment of pyoderma gangrenosum with intravenous immunoglobulin. Br J Dermatol. 2007 Dec;157(6):1235-9. Epub 2007 Oct 4.
  17. Tutrone WD, Green K, Weinberg JM, et al; Pyoderma gangrenosum: dermatologic application of hyperbaric oxygen therapy. J Drugs Dermatol. 2007 Dec;6(12):1214-9.
  18. Foss CE, Clark AR, Inabinet R, et al; An open-label pilot study of alefacept for the treatment of pyoderma gangrenosum. J Eur Acad Dermatol Venereol. 2008 Aug;22(8):943-9. Epub 2008 Apr 1.
  19. Saito N, Yanagi T, Akiyama M, et al; Pyoderma Gangrenosum of the Eyelid: Report of Two Cases and Review of the Dermatology. 2010 Aug 17.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Naomi Hartree
Current Version:
Peer Reviewer:
Dr Laurence Knott
Document ID:
1494 (v23)
Last Checked:
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