What are the treatment guidelines and recommended lab tests for a patient with Henoch-Schönlein Purpura (HSP)?

Treatment Guidelines for Henoch-Schönlein Purpura (HSP)

Initial Assessment and Monitoring

All patients with HSP require urinalysis with microscopy at every clinical visit to detect renal involvement early, looking specifically for proteinuria, red blood cell casts, and dysmorphic red blood cells. 1, 2

Essential baseline laboratory testing includes:

• Urinalysis with microscopy (most critical test) 1, 2
• Quantification of proteinuria (spot urine protein/creatinine ratio or 24-hour collection) 2
• Basic metabolic panel (BUN, serum creatinine) to assess renal function 1, 2
• Complete blood count with platelets to rule out thrombocytopenia 1
• Blood pressure measurement (hypertension indicates severe renal involvement) 1, 2

Renal ultrasound should be performed if renal biopsy is being considered for severe nephritis. 1

Treatment Algorithm Based on Disease Severity

Mild Disease (Joint Pain, Purpura, No Renal Involvement)

Use acetaminophen as first-line analgesic for pain control—avoid NSAIDs including ketorolac (Toradol) as they can cause acute kidney injury in HSP patients. 1, 2

For severe joint pain or widespread cutaneous symptoms, consider oral prednisone 1-2 mg/kg daily for two weeks. 1, 3 However, do NOT use corticosteroids prophylactically at HSP onset to prevent nephritis—moderate quality evidence (Level 1B) shows no benefit in preventing nephritis or reducing risk of severe persistent nephritis. 4, 1, 2

Renal Involvement: Treatment Based on Proteinuria Level

Persistent Proteinuria 0.5-1 g/day per 1.73 m²

Start ACE inhibitor or ARB therapy as first-line treatment, targeting proteinuria to <1 g/day/1.73 m² rather than attempting complete normalization. 4, 1, 2 The American Journal of Kidney Diseases emphasizes that attempting to normalize proteinuria to <0.5 g/day/1.73 m² increases medication side effects without proven benefit. 1

Persistent Proteinuria >1 g/day per 1.73 m² After ACE-I/ARB Trial

If proteinuria remains >1 g/day per 1.73 m² after adequate trial of ACE inhibitor/ARB therapy AND GFR >50 ml/min per 1.73 m², consider a 6-month course of corticosteroid therapy. 4, 1, 2 The KDOQI commentary specifically recommends reserving corticosteroid therapy for nephrotic syndrome (proteinuria >3.5 g/day) or nephritic syndrome that has not improved with ACE inhibitor/ARB therapy. 1

Crescentic HSP with Nephrotic Syndrome and/or Deteriorating Kidney Function

Treat with high-dose intravenous methylprednisolone plus cyclophosphamide, following the same protocol as crescentic IgA nephropathy. 4, 1, 2 This represents the most severe form requiring aggressive immunosuppression. 4

Alternative immunosuppressive agents when needed for severe nephritis include steroids combined with azathioprine, cyclosporine, tacrolimus, or mycophenolate mofetil/mycophenolic acid, though cyclophosphamide remains the only agent with proven efficacy in randomized controlled trials. 4, 5

Renal Biopsy Indications

Perform renal biopsy if:

• Decreased renal function at presentation 2
• Severe nephrotic syndrome (proteinuria >3.5 g/day) 2
• Nephritic syndrome 2
• Deteriorating kidney function 2

Special Populations

Adults with HSP Nephritis

Treat adults with HSP nephritis using the same approach as children, though adults have worse prognosis with protein excretion >1 g/day and higher risk of progression to end-stage renal disease. 4, 1 The American Journal of Kidney Diseases notes that outcome data in adults come from retrospective series showing adults are more likely to have severe initial renal involvement. 4

Adjunctive Supportive Measures

Consider a low-antigen-content (LAC) diet strictly followed for 4-8 weeks, which may improve symptoms and laboratory abnormalities when used in conjunction with other treatments. 1

For persistent purpura and pain, colchicine 1 mg/day may be considered for at least six months. 1

Critical Pitfalls to Avoid

• Do NOT use corticosteroids prophylactically at HSP onset to prevent nephritis (Level 1B evidence shows no benefit) 4, 1, 2
• Do NOT start corticosteroids too early for mild proteinuria without adequate trial of ACE inhibitor/ARB therapy 1
• Do NOT use NSAIDs (like ketorolac/Toradol) for pain control in HSP patients with renal involvement—use acetaminophen instead 1, 2
• Do NOT fail to perform urinalysis at every clinical visit, as this leads to delayed detection of renal relapse 1
• Do NOT delay imaging if an abdominal mass is palpable, as this could represent separate pathology like Wilms tumor 2