Henoch-Schönlein Purpura (HSP)

Definition

• A small-vessel IgA-mediated vasculitis most commonly affecting children aged 2–8 years

• Characterised by a purpuric rash predominantly on the lower limbs and buttocks, often following an upper respiratory tract infection

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Pathophysiology

• IgA deposition in vessel walls leads to inflammation and damage of small blood vessels

• Involves skin, joints, gastrointestinal tract, and kidneys

• Triggered by an immune response post-infection, resulting in systemic vasculitis

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Presentation

• Purpuric rash that is palpable and symmetrical, typically on the lower limbs and buttocks

• Arthralgia or transient arthritis affecting large joints

• Colicky abdominal pain that can mimic appendicitis, with risk of intussusception

• Renal involvement in 25–50% of cases presenting as microscopic or macroscopic haematuria, proteinuria, or even nephrotic syndrome

• Subcutaneous oedema, particularly in the hands, feet, or scrotum

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History and Examination

• History of recent upper respiratory tract infection in approximately 50% of cases

• Document duration of symptoms, severity of joint pain, and gastrointestinal issues

• Inquire about urinary changes such as haematuria or reduced output

• Examination includes careful assessment of the purpuric rash, joint swelling, and abdominal tenderness

• Check for signs of intussusception such as bloody stools and severe abdominal pain

• Evaluate for any dysmorphic features or signs of other systemic involvement

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Management

• Initial workup includes urinalysis to assess for haematuria or proteinuria and blood tests (UEC, urine PCR, coagulation studies which are typically normal)

• Blood pressure monitoring is essential to detect hypertension from renal involvement

• For patients with normal urinalysis or only microscopic haematuria, monitor regularly

• Abnormal findings (significant proteinuria, macroscopic haematuria, or hypertension) warrant prompt paediatric referral

• Symptomatic treatment involves bed rest and limb elevation for subcutaneous oedema

• Provide analgesia with paracetamol 15 mg/kg QID or ibuprofen 10 mg/kg TDS, taking renal function into account

• Severe pain or significant abdominal symptoms may be managed with oral prednisolone 1 mg/kg daily (max 60 mg) until resolution

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Monitoring and Follow-Up

• Follow-up schedule: weekly for the first month, then fortnightly for the next 2–3 months, with reviews at 6 and 12 months

• Regular monitoring of renal function and blood pressure is critical

• Persistent proteinuria, macro haematuria, or hypertension should prompt paediatric nephrology referral

• Ongoing assessment of joint symptoms and abdominal pain is necessary to detect complications early

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Prognosis

• Most cases resolve within 4 weeks without long-term sequelae

• Renal involvement may persist longer and requires ongoing monitoring to prevent chronic kidney disease

• Joint symptoms are generally self-limiting with supportive care

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Notes

• Educate caregivers on the benign and self-limiting nature of the rash and joint symptoms while stressing the importance of follow-up for renal monitoring

• Advise immediate medical review if severe abdominal pain or bloody stools develop, due to intussusception risk

• Ensure comprehensive documentation of all findings to aid in future assessments and differentiate from other vasculitides or coagulopathies