The clinical presentations are highly varied and will depend upon the distribution and extent of organ involvement and size of the involved vessels.

• Systemic: Fever, weight loss, fatigue, myalgia, arthralgia
• Cutaneous: purpura, ulceration, gangrene
• Ocular: red eye, visual loss, diplopia
• Mucocutaneous: oral & genital ulceration
• ENT: Hearing loss (conductive, sensorineural); sinus pain; nasal crusting, epistaxis
• Chest: wheeze, cough, haemoptysis, dyspnoea
• Cardiac: pericarditis, cardiomyopathy, ischaemic chest pain
• Abdomen: Ischaemic abdominal pain, bloody diarrhoea
• CNS: Peripheral neuropathy, mononeuritis multiplex, CN palsy, cord lesions, stroke syndromes
• Renal: blood and protein on urine dipstick, deteriorating renal function

• ESR, CRP – usually elevated
• FBC, U&E, LFTs
• If high clinical index of suspicion check ANCA (MPO/ PR3) – this can be negative.
• Urine dipstick – if positive for blood/protein refer to renal.
• Further investigations are guided by system involved – in many cases additional imaging or biopsies of the affected organ(s) is required to confirm the diagnosis of vasculitis.

Most vasculitidies do not have an associated blood marker. Elevated ANCA levels are associated with the ANCA-associated, small vessel vasculitidies (e.g. Granulomatosis with Polyangiitis, Eosinophillic Granulomatosis with Polyangiitis, Microscopic Polyangiitis, Pauci-Immune Glomerulonephritis). However, in isolation, without other relevant clinical features, elevated ANCA levels are not diagnostic and can be misleading. Elevated ANCA levels can also be related to inflammatory bowel disease, primary sclerosing cholangitis, rheumatoid arthritis, SLE, autoimmune liver disease and some infectious disease.

If vasculitis is suspected then the patient should be referred urgently to the relevant specialty.

• The majority of patients seen with vasculitis are referred by secondary care once other causes have been ruled out.
• Consider referring patients with unexplained systemic symptoms and raised ESR/CRP and/or positive ANCA (MPO/PR3) where there is no evidence of underlying infection or malignancy.
• If vasculitis affects one system only consider direct referral to the relevant specialty:
  • Isolated cutaneous vasculitis – dermatology,
  • Evidence of renal involvement – nephrology,
  • Cerebral vasculitis alone – neurology.

• Those who have known sepsis or malignancy with weakly positive ANCA (MPO/PR3).
• Diagnosis of vasculitis requires confirmation of vasculitic involvement within the symptomatic or dysfunctioning organ(s). Patients who are non-specifically unwell, who do not have localising symptoms or evidence of end-organ dysfunction are unlikely to have a vasculitis.