I located an article titled: Pyoderma Gangrenosum
Authored by J Mark Jackson, MD, Assistant Clinical Professor, Department of Internal Medicine, Division of Dermatology, University of Louisville.
You can locate this article by doing a search with the title and author. Basically it describes the treatments as the standard immune-suppressing regimens: steroids [prednisone], immune-suppressants [cyclosporine, MMF, etc.] and - something that doesn't appear too often - hyperbaric oxygen therapy.
Hyperbaric oxygen therapy is what is normally given deep sea divers suffering from the 'bends'. It's been recently used as a way of improving the delivery of meds into tissues that typically show very poor absorption such as bone, cartilage and skin.
Couldn't locate any clinical trials on the NIH site for your condition, but something may exist if you broaden your parameters to include immune-related dermatitis and other immune disorders where this condition often shows up as another symptom: inflammatory bowel disease [ulcerative colitis, Crohns Disease, chronic hepatitis, rheumatoid arthritis and myeloproliferative disorders.
Here's the clinical trials site link for ulcerative colitis: http://clinicaltrials.gov/ct/gui/act...&submit=Search
rheumatoid arthritis: http://clinicaltrials.gov/ct/gui/act...&submit=Search
The Phase II oral collagen study [7th on the link above] looks interesting and novel; unfortunately, it's limited to those recently diagnosed [2 years or less]. Keep an eye on it just in case they find something worthwhile.