Health condition
Cutaneous vasculitis: the workup
Cutaneous vasculitis - inflammation of small blood vessels in the skin - shows up as crops of raised purple spots (palpable purpura), and the essential task is a structured workup to find the trigger and rule out internal organ involvement.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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Palpable purpura on the lower legs is the classic sign - purple spots you can feel as well as see
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A skin biopsy within 24-48 hours of a new lesion, including immunofluorescence, gives the best diagnostic yield
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Urine dipstick for blood and protein is mandatory - kidney involvement changes management entirely
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Triggers include infections, new medicines, connective tissue disease and, rarely, malignancy; half of cases remain idiopathic
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
When immune complexes lodge in the small vessels of the skin, the vessel walls inflame and leak - producing purpuric spots that do not blanch under pressure, sometimes with blistering or shallow ulcers, usually concentrated on the lower legs where hydrostatic pressure is highest. Burning or itching often accompanies the rash, and joint aches are common.
Diagnosis and treatment routes
The dermatologist takes a fresh-lesion biopsy for standard histology and direct immunofluorescence (which identifies IgA vasculitis), alongside bloods including full blood count, kidney and liver function, ANCA, ANA, complement, hepatitis serology and cryoglobulins, plus urinalysis at every review. Skin-limited disease often settles with rest, support stockings and treating the trigger; colchicine, dapsone or immunosuppression are used for persistent or systemic disease. In much of the UK, a routine NHS referral to the relevant specialist clinic can take several months, whereas an initial appointment with a private consultant is typically available within around two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a consultant dermatologist. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Cutaneous vasculitis: the workup.
Quick, plain-English answers to what people ask us most.
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What is cutaneous vasculitis?
Cutaneous vasculitis is inflammation of small blood vessels in the skin, typically showing up as crops of raised purple spots (palpable purpura), most commonly affecting the lower legs.
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What causes cutaneous vasculitis?
Common triggers include recent infections and certain medications, though it can also be associated with underlying autoimmune conditions or, less commonly, malignancy - which is why a thorough workup matters even when the rash itself looks similar.
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What does the workup for cutaneous vasculitis involve?
A typical workup includes blood tests to check for underlying inflammatory or autoimmune conditions, urine testing to assess for kidney involvement, and sometimes a skin biopsy to confirm the diagnosis and characterise the type of vasculitis.
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Why is a thorough workup needed for a skin rash?
Because cutaneous vasculitis can be an isolated, self-limiting skin problem or a sign of a more significant underlying systemic condition, a proper workup helps identify any underlying cause needing specific treatment and checks for internal organ involvement.
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Is cutaneous vasculitis dangerous?
Many cases are mild and self-limiting, but if there's evidence of internal organ involvement (particularly the kidneys) or an underlying systemic vasculitis, it can be more serious and needs prompt specific treatment.
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How is cutaneous vasculitis treated once the cause is found?
Treatment depends on the cause: removing or treating a triggering infection or medication for straightforward cases, or steroid and immune-modulating treatment for cases linked to an underlying systemic condition.
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How long does the workup take?
Initial blood and urine tests are usually available within days, while biopsy results typically take one to two weeks, giving a reasonably complete picture within a couple of weeks in most cases.
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Does everyone with a purple rash need a full workup?
Most clinicians recommend at least basic screening (urine testing, basic blood tests) for anyone with new-onset cutaneous vasculitis, given the possibility of an underlying trigger or kidney involvement, even when the rash appears mild.
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Cutaneous vasculitis workup vs treatment for a simple allergic rash - how do they differ?
A simple allergic rash workup is usually much more limited, since allergic reactions don't carry the same risk of internal organ involvement that vasculitis can, which is why vasculitis specifically warrants additional testing beyond a standard rash assessment.
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When should I see a specialist for a vasculitis workup?
See a dermatologist or rheumatologist promptly for a new purpuric rash, particularly with other symptoms like joint pain or reduced urine output. A private specialist consultation with appropriate workup is often available within about two weeks.