FFinalistSouthampton · 2027
Child health
AKT · Child health/Oncology

Henoch-Schönlein purpura (IgA vasculitis)

IgA-mediated small-vessel vasculitis (often post-URTI)

Overview

The commonest childhood vasculitis — IgA immune complexes deposit in small vessels. A classic tetrad of palpable purpura, arthralgia, abdominal pain and renal involvement, often after an upper respiratory infection.

Recognise

  • Palpable purpura on the buttocks and extensor legs (symmetrical) with NORMAL platelets
  • Arthralgia/arthritis (knees, ankles)
  • Colicky abdominal pain (risk of intussusception)
  • Renal: haematuria/proteinuria (IgA nephropathy spectrum)

Red flags

  • Severe abdominal pain (intussusception), GI bleeding, hypertension or significant proteinuria (renal involvement)

Differentials & how to tell them apart

ITPisolated LOW platelets; purpura but no arthralgia/abdominal/renal tetrad
Meningococcal sepsisunwell/toxic, rapidly spreading purpura — emergency
Acute lymphoblastic leukaemia (ALL)pancytopenia, blasts on film
Haemolytic uraemic syndromebloody diarrhoea, AKI, MAHA, low platelets

Investigations

Clinical. FBC + film (platelets NORMAL — distinguishes ITP/leukaemia), U&E, urinalysis + BP (renal), coagulation normal; biopsy only if atypical.

Management

Supportive care + BP/urinalysis monitoring for renal involvement

  1. 1Supportive: analgesia, hydration, rest. Check BP and urinalysis to detect renal involvement.Gate: Severe abdominal pain → exclude intussusception (HSP causes the ileo-ileal type); significant proteinuria/AKI → nephrology
  2. 2Monitor urine/BP for weeks–months (nephritis can be delayed); steroids for severe disease.
Supportive + analgesia — most cases; NSAIDs for joints (caution if renal/GI involvement)
Corticosteroids — for severe abdominal pain / significant organ involvement (specialist)

Key points

Platelets are NORMAL in HSP (a vasculitis, not thrombocytopenia) — the key split from ITP. Renal follow-up matters because nephritis can appear late.

Monitor & prognosis

Serial BP + urinalysis for 6–12 months (delayed nephritis).

Usually self-limiting; renal involvement determines long-term outcome.

Source: NICE CKS Henoch-Schönlein purpura; RCPCH