Derm Cases · Dermatology / Gastroenterology / Wound care
OSCE — painful ulcer with violaceous undermined border: diagnose and treat pyoderma gangrenosum
An 8-minute OSCE station on recognising classic ulcerative pyoderma gangrenosum, pathergy, IBD association, exclusion of infection before immunosuppression, and first-line systemic therapy with wound-care principles.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on recognising classic ulcerative pyoderma gangrenosum, pathergy, IBD association, exclusion of infection before immunosuppression, and first-line systemic therapy with wound-care principles.
Brief (to candidate)
A 36-year-old with ulcerative colitis develops a rapidly enlarging, exquisitely painful lower-leg ulcer after minor trauma; the edge is undermined and violaceous. Wound swabs grew mixed skin flora; surgical debridement was planned by the referring team. You have 8 minutes to diagnose pyoderma gangrenosum, stop harmful surgery, and start disease-directed therapy.
[3]Candidate instructions
- State the classic clinical triad of PG.
- Explain pathergy and why aggressive debridement is dangerous.
- List major associated systemic diseases.
- Outline diagnostic approach (clinical diagnosis of exclusion + limited work-up).
- Start first-line systemic therapy and wound-care principles.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Clinical triad | Painful ulcer with undermined violaceous (purple) border; pathergy (new lesions at trauma/surgery/needle sites); frequent systemic disease association[3] |
| Pathergy | Minor trauma triggers or worsens lesions — avoid unnecessary surgery/wide debridement; careful wound care only |
| Associations | IBD (UC/Crohn), rheumatoid arthritis, haematologic malignancy/paraprotein, other neutrophilic disorders; screen GI and haematology as indicated[2] |
| Diagnosis | Clinical + exclusion of infection, vasculitis, arterial/venous ulcer, malignancy; biopsy may support (neutrophilic infiltrate) but is not pathognomonic; culture to exclude primary infection before heavy immunosuppression when feasible[3] |
| Therapy | Systemic corticosteroids first-line for classic ulcerative PG; steroid-sparing (ciclosporin, etc.) and TNF inhibitors/other biologics for refractory or IBD-associated disease; treat underlying IBD concurrently[1][5][6] |
| Wound care | Gentle non-adherent dressings, pain control, compression only if venous disease coexists and PG controlled; infection surveillance |
| Safety communication | Cancel non-essential debridement; explain inflammatory not primarily infectious ulcer; early derm/IBD liaison |
Model key actions
- Recognise painful undermined violaceous ulcer + pathergy as PG, often with IBD.[2][3]
- Stop aggressive surgical debridement; start systemic steroids after reasonable infection exclusion.[5]
- Investigate and treat underlying systemic disease while healing the ulcer.[1][6]
Common errors
- Surgical debridement enlarging the ulcer via pathergy.
- Treating only with antibiotics for colonising flora without immunosuppression when PG is clear.
- Missing IBD/haematologic work-up.
- Delaying steroids for weeks of failed local care alone in classic progressive PG.
- Confusing PG with necrotising infection without senior review when sepsis features dominate (must still exclude true infection).
References6ShowHide
- [1]Maronese CA, Pimentel MA, Li MM, et al. Pyoderma Gangrenosum: An Updated Literature Review on Established and Emerging Pharmacological Treatments. American Journal of Clinical Dermatology, 2022.PMID 35606650
- [2]Rogler G, Singh A, Kavanaugh A, et al. Extraintestinal Manifestations of Inflammatory Bowel Disease: Current Concepts, Treatment, and Implications for Disease Management. Gastroenterology, 2021.PMID 34358489
- [3]Maverakis E, Marzano AV, Le ST, et al. Pyoderma gangrenosum. Nature Reviews Disease Primers, 2020.PMID 33033263
- [5]Dissemond J, Marzano AV, Hampton PJ, et al. Pyoderma Gangrenosum: Treatment Options. Drugs, 2023.PMID 37610614
- [6]Tan MG, Tolkachjov SN. Treatment of Pyoderma Gangrenosum. Dermatologic Clinics, 2024.PMID 38423680
- [7]Thomas KS, Ormerod AD, Craig FE, et al. Clinical outcomes and response of patients applying topical therapy for pyoderma gangrenosum: a prospective cohort study J Am Acad Dermatol, 2016.PMID 27502313