Henoch-Schonlein purpura

🔎 In adults, Henoch–Schönlein Purpura (HSP) can present more insidiously, sometimes with serious organ involvement such as the myocardium.

📖 About

• HSP (IgA vasculitis) is a systemic small vessel leukocytoclastic vasculitis.
• Classically presents with a palpable purpuric rash due to dermal capillary bleeding.
• Organs affected: 🩸 skin, 🦴 joints, 🩺 kidneys, and 🍽️ gastrointestinal tract.

🧬 Aetiology

• Immune complex (IgA) deposition in venules, capillaries, and arterioles.
• Often follows infections (especially Group A Streptococcus and Mycoplasma).

🩹 Clinical Presentation

• Purpuric rash (palpable, non-blanching) mainly on lower limbs and buttocks, sparing trunk/face.
• Arthralgia or arthritis (knees, ankles).
• Abdominal pain ± PR bleeding; can complicate into intussusception.
• Renal involvement: haematuria, proteinuria (risk of nephritis).
• Mostly affects children 👧👦, but adults may have more severe disease.

🔎 Investigations

• Bloods: FBC, U&E, clotting – to exclude other causes of purpura or assess renal function.
• Urinalysis: Look for haematuria & proteinuria (≥2+ is significant).
• Throat Swab & ASOT: To detect Group A Strep triggers.

🧪 Renal Disease Findings

• Complement C3 and C4 levels usually normal (helps differentiate from post-strep GN).
• Skin biopsy: Leukocytoclastic vasculitis with IgA & C3 deposits (immunofluorescence).
• Renal biopsy: In severe cases → focal segmental proliferative GN with mesangial IgA deposits (similar to IgA nephropathy).

💊 Management

• 👶 Children: Usually self-limiting, supportive care only.
• 💧 Hydration, analgesia for arthralgia, monitoring renal function.
• 🧪 Parents/patients can perform daily urine dipsticks at home for early renal involvement.
• ⚠️ Severe cases with renal disease or systemic involvement → consider steroids or immunosuppressants.
• 📉 ~1–5% progress to end-stage renal failure.

🩺 Clinical Pearl

In a child with rash, abdominal pain, and arthralgia, always check the urine for microscopic haematuria and proteinuria. Renal involvement determines long-term prognosis.

Cases — Henoch–Schönlein Purpura (IgA Vasculitis)

• Case 1 — Classic tetrad 👦: A 7-year-old boy presents after a sore throat with a purpuric rash over his buttocks and legs, abdominal pain, and arthralgia. Urinalysis: microscopic haematuria. Diagnosis: HSP with skin, joint, gut, and renal involvement. Managed supportively with hydration, analgesia, and monitoring renal function.
• Case 2 — Severe abdominal pain 🚨: A 9-year-old girl develops colicky abdominal pain, vomiting, and bloody stools. Exam: palpable purpura on legs and peri-umbilical tenderness. Ultrasound: bowel wall oedema. Diagnosis: HSP with gastrointestinal involvement (risk of intussusception). Managed with supportive care, corticosteroids for severe gut symptoms, and surgical input if obstruction suspected.
• Case 3 — Renal involvement 🩸: A 12-year-old boy presents with recurrent episodes of purpuric rash and swollen ankles. Urinalysis: proteinuria + red cell casts. BP 145/95 mmHg. Diagnosis: HSP nephritis. Managed with paediatric nephrology input, ACE inhibitor for proteinuria, and steroids if progressive renal disease.

Teaching Point 🩺: Henoch–Schönlein Purpura is an IgA-mediated small vessel vasculitis, classically in children. Features: palpable purpura (lower limbs), arthritis/arthralgia, abdominal pain, renal involvement. Often follows infection (URTI). Usually self-limiting, but renal disease determines prognosis. Management is supportive; steroids are used in severe abdominal or renal disease.