Pyoderma gangrenosum (PG), a rare and painful ulcerative skin disorder, requires special care because “it’s a challenging diagnosis to make” and is frequently linked to serious comorbid conditions, a dermatologist told colleagues.
PG is also challenging to manage, said Jeffrey Callen, MD, professor and chief of the division of dermatology at the University of Louisville (Ky.), who spoke at the Inaugural Symposium for Inflammatory Skin Disease. “There are multiple treatments, but few have a high level of evidence to document their efficacy.”
PG is a neutrophilic dermatosis that usually occurs with a small lesion, often pustular, that spreads, and is a diagnosis of exclusion. “There’s no way you can possibly exclude everything, but the major things that have to be excluded are infection and malignancies,” he said. “Doing a good history and physical examination is critical, and a biopsy should be done in the vast majority of patients.”
Cultures and routine labs should be obtained, said Dr. Callen, highlighting tests that measure immunofixation (IFE), antineutrophil cytoplasmic antibodies (ANCE), anticardiolipin antibody (aCL), and lupus anticoagulant (LA).
Bowel and bone marrow tests may be appropriate in some patients, he said, noting that about half of PG cases are linked to comorbid conditions such as inflammatory bowel disease (IBD), arthritis, and hematologic diseases.
Dr. Callen also made the following points about making the diagnosis:
- Several clinical variants exist: classic, peristomal, and atypical.
- Pathergy – hyperreactivity of skin to injury – occurs in about a third of patients.
- Neutrophilic infiltrates may occur in other organs.
- Numerous drugs, including isotretinoin, can cause PG.
- PG may be misdiagnosed as necrotizing fasciitis.
- Several diagnostic frameworks exist: the Su Criteria, the PARACELCUS Score, and the Delphi Consensus Criteria. The Delphi criteria identified the highest percentage of cases (89%) in a study comparing the three, published in 2020. The frameworks “are helpful in the clinic, but they are not to be used as criteria for diagnosis. They’re really for classification,” Dr. Callen said.
Once the diagnosis has been made, he said, focus on healing the wound, which he said “can be done as any other wound would be healed,” and calming the inflammation.
“Patients who have mild disease might be treated with lower doses of prednisone, topical medications, or intralesional injections,” he said. “Corticosteroids are never wrong in the beginning.” Some patients may have genetic abnormalities related to PG, he added, and medications that target them may be appropriate.
Antibiotics and biologic agents, particularly TNF-alpha inhibitors, are possible treatments, Dr. Callen said. He highlighted a 2018 systematic review that evaluated treatments and found the most evidence supported systemic corticosteroids, cyclosporine, and TNF-alpha inhibitors. However, the quality of studies was limited, and the authors noted that the lesions frequently failed to respond or recurred.
When appropriate, surgery can be performed, he said.
Dr. Callen reported no relevant disclosures.