Allergic Purpura

Allergic Purpura (Henoch–Schönlein Purpura) – Treatment Overview

Introduction
Allergic purpura, also known as Henoch–Schönlein purpura (HSP) or IgA vasculitis, is an immune-mediated small-vessel vasculitis characterized by deposition of IgA-containing immune complexes. It commonly presents with palpable purpura, abdominal pain, joint pain, and renal involvement (hematuria, proteinuria). It is most frequent in children but can also occur in adults. The disease is usually self-limiting, but treatment is needed to control symptoms and prevent complications.

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Treatment Options and Doses

1. General Supportive Care

• Rest, adequate hydration, and monitoring for renal involvement.

• Avoidance of potential triggers (e.g., certain infections, medications).

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2. Analgesics (for joint and abdominal pain)

• Paracetamol (Acetaminophen): 10–15 mg/kg orally every 4–6 hours (maximum 4 g/day in adults).

• Avoid NSAIDs in patients with renal impairment, though they may be used with caution in mild cases without kidney involvement:

  • Ibuprofen: 10 mg/kg orally every 6–8 hours (maximum 400 mg per dose in children, 2400 mg/day in adults).

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3. Corticosteroids (for moderate to severe cases)

• Indicated in patients with severe abdominal pain, gastrointestinal bleeding, orchitis, or renal involvement.

• Prednisolone: 1–2 mg/kg/day orally for 1–2 weeks, followed by gradual tapering.

• Methylprednisolone pulse therapy: 30 mg/kg IV daily (maximum 1 g) for 3 consecutive days in severe renal involvement.

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4. Immunosuppressive Agents (for severe renal disease)

• Considered when there is nephrotic syndrome, rapidly progressive glomerulonephritis, or persistent proteinuria despite steroids.

• Azathioprine: 1–2 mg/kg/day orally.

• Cyclophosphamide: 1–2 mg/kg/day orally or as IV pulses (500–750 mg/m² monthly).

• Mycophenolate mofetil: 600–1200 mg/m²/day orally in divided doses.

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5. Additional/Supportive Therapy

• Antihypertensives (ACE inhibitors/ARBs): For persistent proteinuria and hypertension.

  • Enalapril: Start at 0.1 mg/kg/day orally, titrate as needed.

• Plasmapheresis or IVIG: Reserved for very severe renal or systemic involvement.