Pyoderma Gangrenosum

Please assess this 55 year old man with a non-healing leg ulcer on his left shin.


HISTORY (3 mins)


  • Timing Questions- since when, sudden/gradual, coming and going versus constant, previous ulcers, ulcers elsewhere, how did it start? And how is it progressing/changing? e.g. getting bigger or more painful
  • Characteristics- where exactly? Size? Painful? Colour e.g. black? Smell?
  • Diabetic? Hypertension? Smoking? Cholesterol? MI?angina?Stroke? (arterial ulcer/diabetic ulcer)
  • Fever? (infection)
  • Pins and needles/numbness? (neuropathic ulcer)
  • Trauma?
  • Varicose veins? DVT? Pregnancies? Long periods of standing? (venous ulcer)
  • Skin/eye/joint problems/mouth ulcers/dry eyes/raynauds (vasculitic ulcer)
  • Bowels/weight loss/abdo pain/PR bleeding (IBD assoc with PG)
  • Fever/night sweats/lymph nodes/bleeding/bruising/back pain (lymphoma/leukaemia/myeloma assoc with PG)
  • Jaundice/itching (PBC assoc with PG)
  • PMH (RA, IBD, blood cancer, DM)
  • Dx including treatments tried already
  • Fx
  • Sx


EXAMINE (3mins)


  • Inspect
    • Count toes! (any amputations?)
    • Lift foot to look at heels, lateral aspects
    • Check for infection/ulcers between toes
    • Inspect leg, ankle joint, foot, toes, nails for scars, pale, thin, shiny skin, hair loss, lipodermatosclerosis, colour, gangrene, calluses, charcot joint, claw toes, ingrowing nails
    • Look at ulcer base, colour, smell, infected looking?, location, size, depth is bone visible?
    • Look at footwear
  • Feel
    • Temperature
    • Cap refill
    • Oedema
    • DP and PT and popliteal pulses
  • Neuro
    • Monofilament to toes, metatarsal heads, heel, dorsum
    • Vibration sense
    • JPS
    • Ankle jerk
  • Quick CVS exam
  • Then proceed according to the history eg. Abdo exam, LNs, inspect rest of skin, hands for arthropathy etc.


ICE and Management (2 mins):


For example:

“There are lots of causes of ulcers.  It could be a problem with the veins/arteries/nerves.  It may be related/unrelated to your inflammatory bowel disease. I need to exclude common causes first; I will test for diabetes today (blood test and urine) and check the blood supply to your feet (ABPI).  We need to make sure it isn’t infected so I’ll do some swabs and blood tests and an xray of your leg. If it is infected I’ll give you antibiotics.

We may need to do a biopsy to have an idea of what we are dealing with.  I’ll liaise with a dermatology doctor.  For now I’ll get you some pain relief and the nurses to redress it.”






  • Bloods: FBC, ESR, CRP, Immunoglobulins, RF, antiCCP, ANA, ANCA, serum electrophoresis, urine BJP, Calcium (to exclude myeloproliferative and connective tissue disease cause), LFTs to rule out PBC/hepatitis, Hba1c, lipid profile (arterial cause)
  • Swabs
  • ABPI pre-compression
  • Xray to rule out osteomyelitis or MRI
  • Biopsy
  • GI colonoscopy if suspect IBD
  • Medical photography


Pyoderma Gangrenosum:


Rare, affects those aged 40-60 usually. Painful nodule/pustule which rapidly progresses to become an enlarging ulcer usually on the legs/trunk. It usually starts quite suddenly, often at the site of a minor injury (pathergy).


Pyoderma= purulent, gangrenosum = black edge


Large necrotic ulcers with ragged bluish-red edges and purulent surface. May occur as an example of koebners phenomenon eg. Don’t miss PG around stoma site


50% have an associated condition:

  • IBD- 50% UC, Crohns
  • RA and seronegative arthritis, SLE, GPA, APS
  • Myeloproliferative disorders- AML, CML, HCL, myelodysplasia, MGUS, MM
  • PBC/Hep C/AIH
  • Idiopathic 20-50%


It is uncommon, chronic and recurrent.

PG should be considered in any non-healing ulcer or wound.

It is a diagnosis of exclusion: histology is variable and often nonspecific: neutrophil infiltration, epidermis necrosis


Management of PG:


Refer urgently to a dermatologist for diagnosis and treatment. Immunosuppression and expert wound care are the main treatments.

The necrotic tissue should be gently removed but wide surgical debridement should be avoided during the active stage of pyoderma gangrenosum because it may result in enlargement of the ulcer.

Antibiotics such as flucloxacillin should be prescribed if bacteria are cultured in the wound (secondary wound infection) or there is surrounding cellulitis (red hot painful skin),

Small ulcers are best treated with potent topical steroid creams, tacrolimus ointment, special dressings

If tolerated, careful compression bandaging can be applied to reduce swelling

Systemic treatment for larger ulcers due to pyoderma gangrenosum may include: high doses of oral prednisone for several weeks or longer, or intermittent intravenous methyl prednisolone for 3–5 days, Ciclosporin, Anti-TNFα inhibitors, Mycophenolate mofetil, Dapsone, Potassium iodide solution, Methotrexate, Cyclophosphamide


The outlook or prognosis for pyoderma gangrenosum is unpredictable.

There may be spontaneous resolution, a quiescent phase for months or years or flare-ups following minimal trauma or for no apparent cause.


Causes of leg ulcers:


  1. Venous
  2. Arterial
  3. Diabetes
  4. Neuropathic
  5. Vasculitic e.g. antiphospholipid syndrome, vasculitic rheumatoid arthritis, systemic lupus erythematosus, Wegener’s granulomatosis, Behçet’s disease.
  6. Infection e.g. Bacterial eg. syphilis •Viral – eg, herpetic ulcers.•Parasitic
  7. Neoplasia eg. SCC, cutaneous lymphoma, Kaposi’s sarcoma
  8. Haematological eg. Sickle cell
  9. Traumatic eg. burns, bites
  10. Pyoderma Gangrenosum
  11. Other e.g. calciphylaxis, cholesterol emboli


Written by Sarah Kennedy



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