What is the recommended management approach for a pediatric patient presenting with Henoch-Schönlein purpura (HSP), joint pain, and purpuric rash, with potential renal involvement?

Management of Henoch-Schönlein Purpura with Renal Involvement in Pediatric Patients

For a pediatric patient with HSP presenting with joint pain, purpuric rash, and potential renal involvement, immediately obtain urinalysis with microscopy, quantify proteinuria, measure blood pressure, and check basic metabolic panel—then stratify treatment based on proteinuria severity: supportive care alone for isolated hematuria or proteinuria <0.5 g/day/1.73 m², ACE inhibitor/ARB for persistent proteinuria 0.5-1 g/day/1.73 m², corticosteroids for nephrotic-range proteinuria >1 g/day/1.73 m² after ACE-I/ARB trial, and high-dose IV methylprednisolone plus cyclophosphamide for crescentic nephritis with deteriorating kidney function. 1, 2

Immediate Diagnostic Workup

• Obtain urinalysis with microscopy to assess for red blood cell casts and dysmorphic RBCs, which indicate glomerular involvement and help determine severity of glomerulonephritis 2

• Quantify proteinuria using spot urine protein-to-creatinine ratio to stratify disease severity and guide treatment decisions 1, 2

• Measure blood pressure as hypertension indicates more severe renal involvement and requires treatment 2

• Check basic metabolic panel including BUN and creatinine to assess baseline renal function 2

• Perform renal biopsy if decreased renal function at presentation, severe nephrotic syndrome (proteinuria >3.5 g/day), nephritic syndrome, or deteriorating kidney function develops 1, 2

Treatment Algorithm Based on Renal Involvement Severity

Minimal or No Renal Involvement (Isolated Hematuria or Proteinuria <0.5 g/day/1.73 m²)

• Provide supportive care only with acetaminophen for joint pain and purpura-related discomfort, as most HSP cases are self-limited with average disease duration of 4 weeks 3, 4

• Avoid NSAIDs (like ketorolac) for pain control in patients with any renal involvement, as they can cause acute kidney injury 2

• Do NOT use corticosteroids prophylactically at HSP onset to prevent nephritis—moderate quality evidence (Level 1B) shows no benefit in preventing or reducing severity of nephropathy 1, 2, 3

Persistent Proteinuria 0.5-1 g/day per 1.73 m²

• Start ACE inhibitor or ARB therapy to target proteinuria reduction to <1 g/day/1.73 m², as this approach is extrapolated from IgA nephropathy treatment guidelines 1, 2, 5

• Maintain blood pressure below 90th percentile for age and gender, targeting 130/80 mmHg when proteinuria is <1 g/day 5

• Monitor response for 3-6 months before escalating therapy, as angiotensin blockade may prevent secondary glomerular injury 3

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

• Add 6-month course of corticosteroid therapy if proteinuria persists >1 g/day/1.73 m² after 3-6 months of optimized ACE-I/ARB therapy and GFR remains >50 ml/min per 1.73 m² 1, 2, 5

• Use oral prednisone 1-2 mg/kg daily for 2 weeks initially, as this regimen has been shown to reduce mean time to resolution of symptoms 4

• Target proteinuria to <1 g/day/1.73 m² rather than complete normalization to <0.5 g/day, as attempting lower targets increases medication side effects without proven benefit 1, 5

Crescentic HSP Nephritis with Nephrotic Syndrome and/or Deteriorating Kidney Function

• Treat with high-dose IV methylprednisolone plus oral cyclophosphamide (2 mg/kg/day for 12 weeks), as this is the only immunosuppressive combination with randomized controlled trial evidence of efficacy 1, 2, 6

• Define crescentic disease as presence of crescents in ≥50% of glomeruli on biopsy with rapidly progressive renal deterioration 1, 2

• Use IV methylprednisolone pulse therapy (1 gram daily for 3 consecutive days) or oral prednisone followed by cyclophosphamide, with concurrent daily or alternate-day oral prednisone 6, 7

• Monitor for hypertension during treatment, as it develops in most patients receiving this regimen but typically resolves after treatment completion 6

Critical Pitfalls to Avoid

• Do NOT delay renal biopsy if patient presents with decreased renal function, severe nephrotic syndrome, or nephritic syndrome, as histopathologic findings guide treatment intensity 1, 2

• Do NOT use corticosteroids for isolated proteinuria <1 g/day/1.73 m² without first attempting ACE-I/ARB therapy, as there is insufficient evidence supporting steroids at lower proteinuria levels 1

• Do NOT assume isolated hematuria requires no evaluation if an abdominal mass is palpable, as this could represent separate pathology like Wilms tumor 2

• Do NOT use mycophenolate mofetil, azathioprine, or cyclosporine as first-line agents for HSP nephritis, as only cyclophosphamide has demonstrated efficacy in randomized controlled trials 5, 7

Follow-Up and Monitoring

• Continue monitoring for at least 6 months after HSP presentation with regular urinalysis for proteinuria and hematuria plus blood pressure measurements 8

• Counsel female patients that women with childhood HSP history are at increased risk of proteinuria and hypertension during pregnancy and require close monitoring 8

• Recognize that long-term prognosis depends on severity of renal involvement, with end-stage renal disease occurring in 1-5% of patients 4