Pyoderma Gangrenosum

A cause of ulcers on the legs

What is pyoderma gangrenosum and how is it diagnosed?

Pyoderma gangrenosum is a condition which often leads to breakdown of the skin.  Its name may be misleading in that it is neither an infection nor gangrene.  Pyoderma gangrenosum is categorized under a set of conditions called neutrophilic dermatoses.  Neutrophils are a type of immune cell which can be seen in conditions where there is inflammation.

How does pyoderma gangrenosum present?

Pyoderma gangrenosum often starts out as a solid pinkish bump or a pus-filled bump.  These bumps can then progress to breakdown or opening of the skin, leading to an ulcer.  Often, the edges may be purplish or greyish, and the borders can become undermined, as if there is an overhanging cliff of skin at the edge.  The base may be coated in yellowish pus.  There are various subtypes in the presentation of pyoderma gangrenosum.  Sometimes it can present with mostly larger blisters or with bulky “vegetative” amounts of skin.  Pyoderma gangrenosum also exhibits pathergy – when areas of the skin are traumatized, this can also incite pyoderma gangrenosum to develop in those areas.  This includes areas of prior surgeries as well as around colostomy sites.  Pyoderma gangreosum may also be quite painful.

When scars of pyoderma gangrenosum ulcers heal, they often are cribriform in appearance, with jagged edges.

What is pyoderma gangrenosum associated with?

In many cases of pyoderma gangrenosum, there is an association with other medical conditions such as inflammatory bowel disease or blood disorders.

How is pyoderma gangrenosum diagnosed?

Pyoderma gangrenosum is a diagnosis of exclusion. This means that your provider needs to exclude an infection before diagnosing you with this condition.

  Neutrophils which are seen in this condition can often be a marker of infection, so it is important to ensure that you do not have evidence of infection.  To exclude infection, biopsies often are done and sent for tissue culture.  Biopsies for pathology examination are often also performed.  Skin biopsies may be performed via punch technique, shave technique, or via a wedge excision.  Areas of biopsy may heal poorly.  Clinical information and examination also are necessary for the diagnosis of pyoderma gangrenosum.  Other factors include presence of pathergy, a certain pattern of scarring with jagged edges, and good response to steroid treatment.  Your provider may also perform other tests such as blood tests to make sure there are no other causes for the ulcers.

How is pyoderma gangrenosum treated?

Ulcers need to receive proper wound care.  In general, dressings which do not further traumatize the skin should be used.  Areas should be kept clean, and basic good wound care principles should be followed to optimize healing.

Treatment of pyoderma gngrenosum depends on the extent of the condition.  If the extent of pyoderma gangrenosum is very limited, treatment may be limited to topical therapy such as topical steroids or topical calcineurin inhibitors (e.g. tacrolimus).  When more extensive, systemic steroids such as those taken by mouth are often used.  Other immunosuppressive medications may also be tried, including but not limited to, TNF-inhibitors (such as infliximab), cyclosporine, minocycline (typically used as an antibiotic but also has anti-inflammatory properties), dapsone (also typically used as an antibiotic but also has anti-inflammatory properties).  Other treatments such as intravenous immunoglobulin (IVIG) have also been used for this condition.

Should pyoderma gangrenosum be treated surgically?

In general, pyoderma gangrenosum should not be surgically debrided. This is because the act of debridement can further incite this condition.  However, in special circumstances, surgical intervention may be warranted, but this should be done with careful consideration.

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