Derm Cases · Dermatology / Vasculitis / Internal medicine
OSCE — palpable purpura on the legs: work-up of cutaneous small-vessel vasculitis
An 8-minute OSCE station on recognising leukocytoclastic cutaneous small-vessel vasculitis, performing skin biopsy with DIF, screening systemic causes and renal involvement, and deciding supportive care versus systemic therapy.
On this page
Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on recognising leukocytoclastic cutaneous small-vessel vasculitis, performing skin biopsy with DIF, screening systemic causes and renal involvement, and deciding supportive care versus systemic therapy.
Brief (to candidate)
A 48-year-old woman develops non-blanching palpable purpuric papules on both lower legs over 5 days after a course of antibiotics for a UTI. She feels well; BP normal. No abdominal pain. You have 8 minutes to diagnose cutaneous small-vessel (leukocytoclastic) vasculitis, plan biopsy and systemic screen, and manage drug-associated disease.
[3]Candidate instructions
- Define palpable purpura and the vessel size implied.
- Plan skin biopsy (H&E + DIF) timing and site.
- Screen for systemic involvement and secondary causes.
- List key differentials (IgA vasculitis, cryoglobulinaemia, infection, ANCA).
- Outline supportive vs systemic treatment and drug cessation.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Recognition | Palpable purpura (non-blanching) on dependent sites, especially legs = hallmark of cutaneous small-vessel / leukocytoclastic vasculitis[1][3] |
| Histology / DIF | Biopsy early lesion for H&E: fibrinoid necrosis, neutrophilic infiltrate, leukocytoclasia, RBC extravasation; DIF on perilesional/early lesion for IgA/C3/immune complexes to subclassify |
| Systemic screen | Urinalysis, BP, creatinine, FBC, CRP/ESR; ask fever, arthritis, abdominal pain, neuropathy, pulmonary symptoms; drug/infection/malignancy history |
| Cause hunt | Drugs (antibiotics, NSAIDs, etc.), infection, autoimmune CTD, malignancy, IgA vasculitis, cryoglobulins/HCV, ANCA if systemic features[5][6] |
| Management | Stop culprit drug; leg elevation, compression if appropriate, analgesia; most idiopathic/skin-limited disease is self-limited; systemic steroids/immunosuppression if ulcerating, necrotic, or extracutaneous disease |
| Safety-net | Reassess renal sediment; escalate if RPGN, multi-organ signs, or progressive ulceration |
| Communication | Explain biopsy rationale and expected time course; document drug allergy if drug-induced |
Model key actions
- Diagnose CSVV/LCV from dependent palpable purpura.[1][3]
- Biopsy with DIF; always check urine/renal and look for drugs/infection.[5]
- Stop culprit antibiotic; supportive care first for skin-limited disease; escalate if systemic.
Common errors
- Calling non-palpable petechiae 'vasculitis' without differential of thrombocytopenia.
- Skipping urinalysis in every vasculitis presentation.
- Missing drug trigger.
- Treating all cases with high-dose steroids without severity assessment.
- Not sending DIF, missing IgA vasculitis subclass.
References4ShowHide
- [1]Shavit E, Alavi A, Sibbald RG. Vasculitis-What Do We Have to Know? A Review of Literature. International journal of lower extremity wounds, 2018.PMID 30501545
- [3]Lotti T, Ghersetich I, Comacchi C, Jorizzo JL. Cutaneous small-vessel vasculitis. Journal of the American Academy of Dermatology, 1998.PMID 9810883
- [5]Fraticelli P, Benfaremo D, Gabrielli A. Diagnosis and management of leukocytoclastic vasculitis. Internal and emergency medicine, 2021.PMID 33713282
- [6]Frumholtz L, Laurent-Roussel S, Lipsker D, et al. Cutaneous Vasculitis: Review on Diagnosis and Clinicopathologic Correlations. Frontiers in medicine, 2021.PMID 32378145