Review the provided adult and pediatric clinical images, brief histories and investigation reports. Identify the likely systemic vasculitides, interpret the important clinical and laboratory findings, and state the major complications and urgent management priorities.

Large-vessel vasculitis: Giant cell arteritis presents with new headache, scalp tenderness, jaw claudication or visual symptoms; elevated ESR/CRP supports inflammation. Sudden visual loss is an emergency.

Medium-vessel vasculitis: Polyarteritis nodosa may cause livedo reticularis, hypertension, abdominal pain and mononeuritis multiplex, usually without glomerulonephritis.

Small-vessel vasculitis: Granulomatosis with polyangiitis causes ENT, pulmonary and renal involvement, often with PR3-ANCA positivity; IgA vasculitis presents with palpable purpura, abdominal pain, arthritis and possible nephritis.

Other characteristic syndromes: Behçet syndrome causes recurrent oral and genital ulcers with possible uveitis; Kawasaki disease presents with prolonged fever and characteristic mucocutaneous findings.

Clinical priority: Assess organ-threatening complications, interpret inflammatory, immunological and renal investigations, and arrange urgent treatment for threatened vision, rapidly progressive renal disease, pulmonary hemorrhage or Kawasaki-associated coronary risk.

1. Identify the vessel pattern: Distinguish large-vessel features such as cranial ischemia, medium-vessel features such as organ ischemia or neuropathy, and small-vessel features such as palpable purpura and glomerulonephritis.
2. Recognize giant cell arteritis: In an older adult, identify temporal headache, scalp tenderness, jaw claudication and visual symptoms. Review ESR/CRP and arrange urgent assessment; suspected visual involvement requires immediate glucocorticoid treatment.
3. Recognize polyarteritis nodosa: Look for livedo reticularis, painful nodules, hypertension, abdominal ischemic pain and mononeuritis multiplex. Assess renal function, urinalysis and possible hepatitis B association.
4. Recognize granulomatosis with polyangiitis: Identify chronic sinus symptoms, nasal crusting, hemoptysis, pulmonary nodules and nephritic urine findings. Interpret PR3-ANCA, creatinine, urinalysis and relevant imaging.
5. Recognize IgA vasculitis and Behçet syndrome: For IgA vasculitis (Henoch-Schönlein purpura), identify lower-limb palpable purpura, abdominal pain, arthritis and renal involvement. For Behçet syndrome, identify recurrent oral/genital ulcers and ocular inflammation.
6. Assess Kawasaki disease: Recognize fever for at least five days with bilateral non-purulent conjunctivitis, oral changes, polymorphous rash, extremity changes or cervical lymphadenopathy. Select echocardiography to assess coronary involvement.
7. Interpret and prioritize: Correlate ESR/CRP, ANCA where appropriate, urine findings, renal function and organ-specific investigations. Urgently escalate suspected visual ischemia, pulmonary-renal syndrome, severe abdominal ischemia or Kawasaki disease requiring prompt treatment.

Examiner’s note: ANCA positivity supports the diagnosis of an appropriate vasculitic syndrome but is not diagnostic alone; negative ANCA does not exclude vasculitis. Interpret serology alongside clinical findings, urinalysis, organ investigations and biopsy when indicated.

⚠️ Urgent clinical priorities: Do not delay glucocorticoid treatment when giant cell arteritis threatens vision. Suspected pulmonary hemorrhage or rapidly progressive glomerulonephritis requires emergency specialist assessment. Kawasaki disease requires prompt pediatric evaluation and treatment to reduce coronary complications.