HSP

Henoch–Schönlein Purpura (HSP)

Henoch–Schönlein Purpura (HSP), now more commonly known as IgA vasculitis, is the most common systemic vasculitis of childhood. It’s a small-vessel vasculitis that primarily affects the skin, joints, gastrointestinal tract, and kidneys. HSP is usually a self-limiting condition, with the prognosis being determined by the degree of renal involvement.

 

Clinical Presentation

HSP is diagnosed based on a combination of clinical features. The classic tetrad of symptoms includes:

  • Skin: A palpable purpuric rash is the hallmark feature and is present in virtually all cases. The rash is non-blanching and symmetric, typically affecting the lower limbs and buttocks.

  • Gastrointestinal (GI): Abdominal pain is common and can be severe, sometimes preceding the rash. Other symptoms include vomiting, diarrhoea, and bloody stools. Intussusception is a serious, although rare, complication to be aware of.

  • Musculoskeletal: Joint pain (arthralgia) and swelling, particularly of the ankles and knees, are common.

  • Renal: Kidney involvement is a key determinant of prognosis. It can range from mild microscopic haematuria to more severe disease with proteinuria, nephrotic syndrome, or acute kidney injury.

 

Investigations and Differential Diagnoses

  • Investigations: There is no specific diagnostic test for HSP. Investigations are aimed at supporting the diagnosis and, more importantly, ruling out other, more serious conditions.

    • Urinalysis: Perform a urinalysis to check for haematuria and proteinuria. A first void urine protein/creatinine ratio is useful to quantify proteinuria.

    • Bloods: A baseline FBC, U&Es, and clotting screen should be performed.

  • Differential Diagnoses:

    • Meningococcal Sepsis: A non-blanching rash can be a sign of meningococcal septicaemia. The rash in HSP is palpable and usually symmetric.

    • Thrombocytopenia: A low platelet count can cause a similar rash. An FBC and blood film will help differentiate this.

    • Leukaemia: A diagnosis of exclusion, to be considered if there are other systemic symptoms or abnormal blood counts.

 

Management

  • Supportive Care: Most cases are self-limiting and are managed with supportive care. This includes ensuring adequate hydration, nutrition, and pain relief.

  • Analgesia: Simple analgesics like paracetamol can be used for joint pain. NSAIDs should be used with caution and are contraindicated if there is any evidence of renal involvement.

  • Corticosteroids: Oral corticosteroids may be considered for severe abdominal pain or musculoskeletal symptoms, but they do not prevent renal involvement.

  • Renal Management: Renal involvement is managed in a step-wise approach.

    • Monitoring: All children with HSP should have their urine monitored for a full 12 weeks after the onset of the rash to check for haematuria and proteinuria.

    • Nephrology Referral: Referral to a paediatric nephrologist is required for any child with hypertension, significant proteinuria (2+ or more), or evidence of renal impairment on blood tests.

  • Surgical Referral: A surgical review is needed if there is a suspicion of intussusception, which can present as severe abdominal pain with a palpable mass.