Pyoderma gangrenosum


Pyoderma gangrenosum

What is pyoderma gangrenosum?

Pyoderma gangrenosum is a rare cause of chronic, recurrent and painful non-infectious skin ulcers. It is classified as a neutrophilic dermatosis (skin disorder that has dense infiltration of inflammatory cells called neutrophils). It affects both males and females but is more common in females aged between 20 and 50 years. It rarely affects infants and children.

Pyoderma gangrenosum
Image reproduced with permission of Clinical Associate Kurt Gebauer

What causes pyoderma gangrenosum?

The cause of this condition is unknown. It is commonly associated with an underlying autoimmune condition (when our own immune cells attack our body). Minor skin injuries may also trigger the development of these ulcers.

What does pyoderma gangrenosum look like?

The appearance of the condition varies from person to person. Lesions appear as small pus-filled pimples, red bumps or blood-filled blisters. These lesions turn into painful ulcers with pus and grow in size very quickly. There is usually a single large lesion. However, multiple lesions can also appear simultaneously.  They can appear with other symptoms such as fever, muscle aches and joint pains. Although lesions can appear on any part of the skin, the lower legs and hands are most commonly involved.

What other problems can occur with pyoderma gangrenosum?

The condition is commonly associated with an underlying disease such as inflammatory bowel disease (e.g. ulcerative colitis or Crohn’s disease), arthritis or bone marrow disorder (e.g. a myeloproliferative disorder).

How is pyoderma gangrenosum diagnosed?

It is difficult to diagnose pyoderma gangrenosum as there is no specific test for the condition. It is important to rule out other causes for ulcers such as trauma, infection, problems with blood vessels (venous or arterial insufficiency) and drug reactions.

The treating doctor will take a detailed past medical history and blood tests will be needed to look for any medical condition. A skin biopsy is needed to rule out other causes for the ulcers but, unfortunately, although supportive, it is not diagnostic for the disease. A wound swab and tissue culture may be needed if a bacterial infection is suspected.  Further testing may be required if an underlying medical condition is suspected.

The final diagnosis will be based on all the clinical and laboratory information.

How is pyoderma gangrenosum treated?

The aim of treatment is to control the inflammation and treat any underlying disease. There are two main forms of anti-inflammatory treatment:

  1. Local therapy

Strong topical corticosteroids and calcineurin inhibitors can be applied to the affected lesions. Steroids may be injected into the lesions to reduce inflammation. When lesions are present on the legs, the doctor may suggest elevating the legs and applying compression bandaging with caution to reduce swelling. Bio-occlusive dressings may also facilitate wound healing when there is no active infection or inflammation.

  1. Systemic (oral, subcutaneous, intramuscular or intravenous) therapy

Oral steroids are used to reduce inflammation together with immunosuppressive agents such as cyclosporin, cyclophosphamide, methotrexate, tacrolimus, TNF-alpha inhibitors, azathioprine, mycophenolate mofetil, immunoglobulins. Side effects of these medications need to be monitored closely by a doctor.

Surgery should be avoided as it can lead to enlargement of the lesions.

What is the likely outcome of pyoderma gangrenosum?

Pyoderma gangrenosum is a treatable condition but it may take months to heal completely. When the underlying disease is treated, the lesions tend to improve. As affected individuals have different medical illnesses and lesions differ in their severity, the outcome of pyoderma gangrenosum differs from person to person.

Regular follow-up with the treating doctor is crucial for close monitoring of the condition. The adverse effects of oral therapy should be discussed thoroughly with a doctor prior to and during treatment.

This information has been written by Dr Shelley Ji Eun Hwang & A/Professor Pablo Fernandez-Penas
Updated 27 July 2015


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