IgA vasculitis — palpable purpura, abdominal pain, and renal follow-up

Questions

a) What is the most likely diagnosis? Give four supporting features. (2 marks)

b) List the first-line investigations and state what abnormality you are specifically looking for in each. (3 marks)

c) Outline management if the child remains stable but has severe abdominal pain. Include analgesia, corticosteroid use, and what must be excluded. (2 marks)

d) State the renal follow-up plan and referral triggers. (3 marks)

Model answer

a) Diagnosis and supporting features (2 marks). The diagnosis is IgA vasculitis (Henoch-Schönlein purpura), an IgA immune-complex small-vessel vasculitis. Supporting features are palpable non-blanching lower-limb or buttock purpura with a normal platelet count, preceding upper respiratory infection, ankle arthralgia or arthritis, colicky abdominal pain, and haematuria or proteinuria on urine dipstick.^[1][3]

b) Investigations (3 marks). First-line tests are FBC with platelet count to exclude thrombocytopenic purpura; urea, creatinine, electrolytes and eGFR to stage renal involvement; urinalysis plus urine protein-to-creatinine or albumin-to-creatinine ratio if protein is present; blood pressure measurement because hypertension indicates renal disease; stool occult blood if GI symptoms are present; and CRP or cultures only if infection or sepsis is a realistic alternative. Skin biopsy is reserved for atypical, adult, severe, or uncertain cases and should show leukocytoclastic vasculitis with IgA-dominant direct immunofluorescence.^[1][2]

c) Management of severe abdominal pain (2 marks). Give supportive care with hydration, paracetamol and antiemetic as needed, escalate analgesia if severe, and assess for dehydration or GI bleeding. Severe colicky pain, vomiting, guarding, distension, melaena or haematochezia requires urgent abdominal ultrasound and senior paediatric or surgical review to exclude intussusception or bowel ischaemia. Corticosteroids such as prednisolone about 1 to 2 mg/kg/day may be used for severe vasculitic abdominal pain after surgical emergencies are considered; they do not remove the need for renal follow-up.^[1][3]

d) Renal follow-up and referral (3 marks). Every patient needs documented urinalysis and blood pressure surveillance for at least six to twelve months because nephritis may appear after the rash settles. Quantify proteinuria whenever dipstick protein is present and repeat renal function if urine or BP is abnormal. Refer urgently to nephrology for hypertension, rising creatinine or reduced eGFR, macroscopic haematuria with renal impairment, nephritic syndrome, nephrotic syndrome, rapidly progressive glomerulonephritis, or persistent/significant proteinuria. ACE inhibitor or ARB therapy for persistent proteinuria and immunosuppression are nephrology-led decisions.^[2][3]