Publish date: Posted on
Last updated: October 21, 2023
Keywords #
pyoderma gangrenosum
neutrophilic dermatoses
inflammatory dermatoses
Diagnosis #
Pyoderma gangrenosum (PG) is a rare, noninfectious, neutrophilic dermatosis that presents with inflammatory ulcerations of the skin.[1] Clinical, histopathologic, and laboratory findings in PG are nonspecific. Diagnosis is made after other inflammatory and ulcerative cutaneous disorders have been excluded through clinical history, physical exam, and skin biopsy. PG should be considered in patients with known associated conditions, and similarly, the same conditions should be tested for in the presence of PG. The following diagnostic criteria have been developed:[2]
| Major | Minor |
|---|---|
|
|
Definitive diagnosis is obtained when the major and at least four minor criteria are met.[2]
Key Concepts #
- PG is a rare, non-infectious, neutrophilic dermatosis that causes large, painful ulcers, most often on the lower extremities.
- Lesions demonstrate pathergy (arise or exacerbated by trauma, i.e. surgical sites).
- Cause is unknown. Can be idiopathic, but it is frequently associated with inflammatory bowel disease, rheumatoid arthritis, and hematologic malignancies.
- Often treatment resistant, but prednisone, cyclosporine, dapsone, azathioprine, or TNF inhibitors may be used; prednisone is the most common first line treatment.
- Fully evolved lesions have characteristic, undermined, gunmetal grey borders with surrounding erythema and deep central ulceration.
Epidemiology #
PG affects an estimated 3 to 10 people per million per year.[3] Individuals of any age and ethnicity may be affected, but average age of onset is 40-60 years old and women are more frequently affected than men.[4]
Clinical Features #
- Clinical manifestations of PG vary and can be divided into four major subtypes: ulcerative (classic), bullous (atypical), pustular, and vegetative.[1]
- All subtypes share a disease course characterized by initial appearance of an inflammatory papule, pustule, or vesicle that subsequently expands and ulcerates.[1]
- Lesion development is often rapid and very painful.
- Fever may or may not be present.
- Most cases are associated with an underlying systemic disease such as inflammatory bowel disease, rheumatoid arthritis, or hematologic disorders.
- Pathergy is also frequently described in association with PG, but data on the percentage of cases associated with sites of trauma is limited.[1]
Differential Diagnoses #
- Vascular occlusion disorders
- Venous disease
- Vasculitis
- Malignancy
- Infection (i.e. necrotizing fasciitis)
- Drug reactions
- Cutaneous Crohn’s disease
Differentiating diagnoses is important as the association with pathergy can lead to significant morbidity and deformity if aggressive debridement is pursued.[6]
Given the lack of definitive testing and pathognomonic findings, misdiagnosis is relatively common. 10% of PG cases in one study were subsequently found to have another diagnosis.[5]
Diagnostic Workup #
Clinical history, physical exam, and biopsy can be sufficient to diagnose PG, but additional testing may be warranted depending on the other diseases being considered. Laboratory studies including complete blood count, ESR, rheumatoid factor, serum protein electrophoresis should be considered along with colonoscopy, tissue cultures and imaging, if indicated.
Perform a biopsy from the edge of an ulcer (so that epithelium is present). Nonspecific ulceration is seen, and adjacent dermis shows acute and chronic inflammation. Focal and sterile abscesses are surrounded by granulomatous inflammation, bordered by a rim of lymphocytes and plasma cells; eosinophils are variable. Hemorrhage is common, and there is often acanthosis and pseudoepitheliomatous hyperplasia. Leukocytoclastic vasculitis may be seen, but this is thought to be secondary, in response to inflammation, and not a primary process.
Treatment #
Treatment is often difficult and aimed at reducing pain and inflammation. First-line therapies include wound care, pain management, and either systemic glucocorticoids, topical, or intralesional corticosteroids; depending on the extent of disease.[7] Systemic cyclosporine and topical calcineurin inhibitors (tacrolimus, pimecrolimus) have also shown success, with other immunosuppressive drugs used as second-line therapy. These drugs include infliximab and other TNF-alpha inhibitors, dapsone, and minocycline.[7] Surgery should be performed only with extreme caution as any trauma may exacerbate the condition.[5]
Slide Viewer #
https://utahderm.med.utah.edu/image-viewer/References #
- Schadt, Courtney, J. Callen, and A. Ofori. “Pyoderma gangrenosum: pathogenesis, clinical features, and diagnosis.” Waltham, MA (2014).
- Maverakis, Emanual, et al. “Diagnostic criteria of ulcerative pyoderma gangrenosum: a Delphi consensus of international experts.” JAMA dermatology 154.4 (2018): 461-466.
- Monari, Paola, et al. “Epidemiology of pyoderma gangrenosum: Results from an Italian prospective multicentre study.” International wound journal 15.6 (2018): 875-879.
- Binus, A. M., et al. “Pyoderma gangrenosum: a retrospective review of patient characteristics, comorbidities and therapy in 103 patients.” British Journal of Dermatology 165.6 (2011): 1244-1250.
- Weenig, Roger H., et al. “Skin ulcers misdiagnosed as pyoderma gangrenosum.” New England Journal of Medicine 347.18 (2002): 1412-1418.
- Touil, Leila L., et al. “Postsurgical pyoderma gangrenosum versus necrotizing fasciitis: can we spot the difference?.” Annals of plastic surgery 78.5 (2017): 582-586.
- Schadt, Courtney. “Pyoderma gangrenosum: Treatment and prognosis.” UptoDate on-line medical textbook (2017).
