MIAMI -- Keep pyoderma gangrenosum up high in the differential if a wound on the lower extremities does not look or act like a typical venous ulcer.
Making the diagnosis of this recurrent inflammatory ulcer is critical because the treatment differs from that of other types of ulcers, Dr. Francisco A. Kerdel said at a meeting on wound healing sponsored by the University of Miami.
Pyoderma gangrenosum can occur anywhere on the body, but the diagnosis tends to be particularly confusing when it develops on the lower leg, where it can mimic venous ulcers.
But unlike venous ulcers, the lesions of pyoderma gangrenosum commonly have an undermined border that is often gray and indicates the ulcer is penetrating under the epithelium. Another distinction is that the ulcers heal with irregular cribriform scars, said Dr. Kerdel, professor of clinical dermatology at the university.
If necrosis is visible, it's particularly important to rule out pyoderma gangrenosum before debriding the area because the condition is associated with pathergy. "When you traumatize the tissue, you get more disease. If you monkey around with the necrotic tissue, you'll have an ulcer that goes all the way from the knees to the toes," Dr. Kerdel warned.
Pyoderma gangrenosum also does not act like a typical venous ulcer in that the tissue often heals and then breaks down, followed by more healing and more breakdown.
A biopsy will help sort out the diagnosis. It will show numerous polymorphonuclear leukocytes, creating a very dense infiltrate that can extend from the superficial dermis to the subcutaneous tissue. There is a lack of vasculitis.
Observation of the biopsy site for evidence of pathergy also can help clinch the diagnosis.
Unlike venous ulcers, for which compression is the mainstay of therapy, treatment of pyoderma gangrenosum usually involves corticosteroids to address the inflammatory component of the disease. In minimal disease, intralesional steroids may be sufficient. In more extensive disease, intravenous high-dose pulse steroids may be needed, Dr. Kerdel said.
A wide range of other therapies have been used with success. These include dapsone, sulfapyridine, and minocycline. Severe disease has been treated with immunosuppressants such as cyclophosphamide, chlorambucil, cyclosporine A, azathioprine, and tacrolimus, as well as hyperbaric oxygen.
In about half of cases pyoderma gangrenosum is associated with other conditions. These include inflammatory bowel disease, rheumatoid arthritis, IgA gammopathy, and myeloproliferative disorders.
COPYRIGHT 2000 International Medical News Group
COPYRIGHT 2001 Gale Group
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