Page last updated:
5th June 2023

Pyoderma Gangrenosum


In rare cases, some leg ulcers are caused by a condition called Pyoderma Gangrenosum, often known as PG. It is very important that you see your doctor or nurse if you have any wound on your leg or foot so you can get an accurate diagnosis and start the correct treatment.

A diagnosis of Pyoderma Gangrenosum can be quite scary. Like all conditions, having a diagnosis is the first step to getting the correct treatment so that the wound heals.

Symptoms – what is Pyoderma Gangrenosum?

The condition usually starts with one single ulcer; this can unfortunately deteriorate quite quickly to a large or deep wound. Occasionally there may be multiple ulcers. Pain or discomfort from the ulcer is common from the outset.

How the ulceration presents is dependent on your skin tone; for those with lighter skin tones, the edge of the ulcer initially may look purplish, for those with darker skin tones the ulceration may look darker. Sometimes the person may remember that it started like a raised or red nodule or blood blister – sometimes people think they had a nasty insect bite. Pyoderma Gangrenosum is not a skin cancer and does not lead to cancer.

What is Pyoderma Gangrenosum?

Pyoderma Gangrenosum is a rare but treatable cause of skin ulceration. It can happen anywhere on the body – it can start spontaneously or start following a surgical procedure. Pyoderma Gangrenosum lesions or wounds on the leg can be slow to heal because wounds on the legs heal more slowly that other parts of the body.

Despite its name, it is not a type of gangrene. Pyoderma Gangrenosum is not contagious and cannot be passed from person to person.

What does Pyoderma Gangrenosum look like?

What does Pyoderma Gangrenosum looks like? And image of Pyoderma Gangrenosum on a leg

Causes – what can cause Pyoderma Gangrenosum?

The cause of Pyoderma Gangrenosum is often not known. Approximately half the people diagnosed have no known cause for it. It may start after trauma to the skin. Pyoderma Gangrenosum can sometimes be associated with an underlying medical condition such as inflammatory bowel disease, arthritis or certain blood disorders. It is important to know that having Pyoderma Gangrenosum does not mean that you have these conditions but your specialist or doctor will consider and exclude these.

Shaun's story
Read Shaun's story – “A leg ulcer left me unable to work and living in my car”

Diagnosis – getting diagnosed with Pyoderma Gangrenosum

There is no specific blood test for Pyoderma Gangrenosum.

If your nurse or doctor thinks you might have it, they may ask for some tests, including:

  • Taking a small sample at the edge of your wound (biopsy) to establish the presence of Pyoderma Gangrenosum or help rule out other causes of skin ulcers
  • Taking a swab of the wound to check for any infection
  • Blood tests to check for conditions associated with Pyoderma Gangrenosum

If Pyoderma is suspected you should be referred onto a specialist, usually a dermatologist who will confirm a diagnosis and advise you on treatment options.

Pyoderma Gangrenosum can be difficult to diagnose because it does not always show the classic signs of the disease, it may be confused with other conditions and even the biopsy may not detect it.

Thus a diagnosis can be delayed BUT a diagnosis can be given because the consultant now knows what ‘it is not’. In these circumstances it is a ‘diagnosis of exclusion’ and sometimes can be tricky. Thus it becomes important for the patient to describe their symptoms and history well and to not worry that you are pestering the medical team for answers. You need a diagnosis so that treatment can start.

Treatment – how to treat Pyoderma Gangrenosum

Pyoderma Gangrenosum is often difficult to treat and may take some time to heal. Treatment requires the following important interventions.

Medical management by a dermatologist

The consultant aims to get the inflammatory condition under control. Oral medication may include steroids, special antibiotics OR immunosuppressive medication. A topical steroid ointment may be applied directly to the wound. More than one treatment may need to be tried; this will be based on the patient’s experience of the medication and whether the wound shows a positive response to the chosen medication.

The patient will need regular medical review and regular blood tests to ensure the medication is not causing additional problems.

Management of pain

Management of pain is essential – this condition can be extremely painful and the patient will need strong analgesia initially. Please assess for and manage neuropathic pain. Anti-neuropathic medication will be required if compression is to be tolerated. Pain will reduce if the inflammatory condition is being controlled.

Compression therapy (may include bandages or wraps)

Compression is an essential part of the treatment if you have PG on your legs or feet and can get forgotten. Medical management may not be enough on its own to control this condition or any associated swelling. Even if the leg is not very swollen the compression bandage or sock will reduce the level of exudate and make the wounds less wet. You may want to start with mild compression, but increase the level of compression as soon as you can so the patient can benefit from the anti-inflammatory properties of the compression therapy.

Where’s the harm?

  • Pyoderma Gangrenosum on the legs needs compression therapy alongside the medical management
  • The powerful anti-inflammatory effects of compression therapy can get missed whilst the doctors focus on establishing the correct medication
  • Whilst PG is not caused by venous hypertension, any wound on the leg heals faster with compression therapy

Other support

Accelerate Based in East London, Accelerate can accept national referrals from your GP / specialist to our world-class centre where we pioneer and trial experimental new treatments for chronic leg ulcers / wounds, lymphoedema and mobility challenges.

Contact details
020 3819 6022
Find out more on the Accelerate website

The Lindsay Leg Club Foundation Promoting and supporting community based treatment, health promotion, education and ongoing care for people who are experiencing leg-related problems - including leg ulcers and other wound care issues.

Contact details
01473 749565
Find out more on the Lindsay Leg Club Foundation website

NHS Choices the official NHS website, which provides vital information and support about leg and foot signs and other symptoms.

Contact details
Call 111 - for non-emergency medical advice
Find out more on the NHS Choices website

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