Vasculitic rashes
Palpable purpura and other vasculitic rashes. Reading vessel size from morphology, the causes (drugs, infection, IgA vasculitis, cryoglobulinaemia, ANCA vasculitis, connective tissue disease), the urinalysis every patient needs, biopsy timing with direct immunofluorescence, and when skin vasculitis needs urgent systemic treatment.
Tier 2Approach to a presentation
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- The classic vasculitic rash is palpable purpura on the lower legs: non-blanching, raised because the vessel wall is inflamed.
- Morphology tells vessel size, and vessel size narrows the cause. Retiform (branching) purpura usually means occlusion, not vasculitis (see the pattern approach).
- About half of cutaneous small-vessel vasculitis is idiopathic and self-limiting over 3 to 4 weeks. The job is to find the cause and the organ involvement, especially the kidney.
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Sources
- Therapeutic Guidelines: RheumatologyAU/NZTherapeutic Guidelines Limited, 2024 content update (accessed November 2026)
- Jennette JC et al. 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis Rheum 2013;65:1-11American College of Rheumatology, 2012 (still current, November 2026)
- Sunderkötter CH et al. Nomenclature of cutaneous vasculitis: dermatologic addendum to the 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis Rheumatol 2018;70:171-184American College of Rheumatology, 2018
- Hellmich B et al. EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update. Ann Rheum Dis 2024;83:30-47EULAR, 2022 update (no newer EULAR update found, November 2026)
- KDIGO 2025 Clinical Practice Guideline for the Management of IgA Nephropathy and IgA Vasculitis. Kidney Int 2025;108(4S):S1-S71Kidney Disease Improving Global Outcomes (KDIGO), 2025
- Frumholtz L, Laurent-Roussel S, Lipsker D, Terrier B. Cutaneous vasculitis: review on diagnosis and clinicopathologic correlations. Clin Rev Allergy Immunol 2021;61:181-193Clinical Reviews in Allergy and Immunology, 2021
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy