Henoch-Schonlein Purpura

Key points

• IgA vasculitis (IgAV; formerly Henoch–Schönlein purpura) is an IgA-mediated small-vessel vasculitis, usually affecting children and often following an infection.
• Palpable purpura , often with dependent distribution over the buttocks and lower limbs, is characteristic; localized oedema can occur.
• Abdominal pain is a common systemic manifestation and may be colicky or associated with gastrointestinal bleeding.
• Arthralgia/arthritis , particularly of the lower limbs, is a typical extrarenal manifestation.
• Renal involvement may cause haematuria, proteinuria, hypertension and reduced kidney function; severe IgA vasculitis nephritis can rarely present as RPGN.
• Management: supportive care is central. Current KDIGO 2025 guidance does not support routine systemic glucocorticoids solely to prevent nephritis; patients with significant proteinuria, reduced eGFR or rapidly progressive disease require specialist nephrology assessment and risk-based treatment.
• MRCP discriminator: palpable purpura + abdominal pain + arthralgia in a child → IgA vasculitis; haematuria occurring during/within days of a URTI without systemic vasculitis → IgA nephropathy.
• Exam trap: absence of renal involvement does not exclude IgA vasculitis; renal involvement determines long-term kidney risk.