Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Skin findings may mark systemic vasculitis
Necrosis, rapidly spreading purpura, haemodynamic illness, pulmonary symptoms, abdominal pain, neurological deficit or nephritic urine means the process cannot be managed as an uncomplicated skin-limited eruption.
Action: Assess sepsis and organ perfusion immediately, obtain blood cultures and urine and renal testing, photograph and biopsy active lesions when safe, and arrange same-day dermatology and organ-specialist care without waiting for outpatient autoantibodies.
Synopsis
Recognise palpable-purpuric small-vessel inflammation, separate skin-limited disease from systemic vasculitis and mimics, biopsy the correct lesions, remove triggers and escalate only persistent, ulcerating or organ-associated disease.
The hallmark is palpable non-blanching purpura, usually in crops on dependent lower legs; vesicles, bullae, pustules, urticarial plaques, ulcers or necrosis can occur.
Cutaneous small-vessel vasculitis describes a vessel pattern and distribution, not one cause; always decide whether disease is skin-limited, systemic or secondary to infection, medicine, autoimmunity or malignancy.
At the first assessment check observations, blood pressure, urine dip, creatinine, FBC and symptoms from lungs, kidneys, bowel and nerves before calling the eruption benign.
Key red flags
Breathlessness, haemoptysis, falling oxygen saturation or bilateral infiltrates raises diffuse alveolar haemorrhage or infection and requires acute admission.
Systemic vasculitis signal
Haematuria, breathlessness, abdominal pain, bleeding, fever, weight loss or focal neuropathy accompanying purpura moves assessment beyond skin-limited disease.
Investigation priorities
01
First-line observations, urine and renal profileFirst stepFirst line
Identify sepsis, hypertension and silent glomerular involvement at the initial encounter.
Management branches
First-line triageDecide skin-limited or systemic
A new non-blanching palpable eruption is identified.
Record observations and blood pressure, examine lesion morphology and perfusion and ask systematically about renal, pulmonary, bowel, neurological and infectious symptoms.
Perform urine dip, FBC, renal and liver tests and inflammatory markers and arrange same-day escalation for toxicity, necrosis or any organ signal.
Skin-limited first-line careRemove pressure and the driver
The patient is well, baseline organ assessment is reassuring and lesions are non-necrotic.
Key medicines
Colchicine for recurrent skin-limited vasculitisA common specialist off-label trial is 500 micrograms orally once daily, increasing to 500 micrograms twice daily if needed and tolerated; review response after several weeks and stop if ineffective.
DapsoneSpecialists commonly start 50 mg orally once daily and may increase to 100 mg once daily according to skin response and blood safety; cutaneous small-vessel vasculitis is an off-label indication.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.