What is the difference in management between Henoch-Schönlein Purpura (HSP) and low platelet purpura, particularly Immune Thrombocytopenic Purpura (ITP)?

Management Differences Between Henoch-Schönlein Purpura (HSP) and Immune Thrombocytopenic Purpura (ITP)

The primary difference in management between HSP and ITP is that HSP is treated with supportive care and corticosteroids for organ involvement, while ITP requires platelet-increasing therapies such as IVIg, anti-D immunoglobulin, or corticosteroids based on bleeding risk.

Diagnostic Differences

HSP Diagnosis

• Characterized by palpable purpura without thrombocytopenia, plus at least one of: diffuse abdominal pain, arthritis/arthralgia, or renal involvement (hematuria/proteinuria) 1, 2
• Primarily a clinical diagnosis with IgA-mediated small vessel vasculitis 2
• Biopsy shows leukocytoclastic vasculitis with IgA immune deposits in vessel walls 3
• Laboratory findings usually normal, though some cases may show low C3 complement levels 4

ITP Diagnosis

• Defined as isolated thrombocytopenia (platelet count <100 × 10^9/L) without other obvious causes 5
• Diagnosis of exclusion requiring normal peripheral blood smear except for reduced platelets 5
• Platelets may appear larger than normal but giant platelets should be absent 5
• No specific diagnostic test; bone marrow examination only needed in atypical cases 5

Treatment Approaches

HSP Management

• Most cases (94% in children, 89% in adults) resolve spontaneously, requiring only supportive care 1
• Oral prednisone (1-2 mg/kg daily for two weeks) may be used for severe abdominal pain and joint symptoms 1, 2
• Corticosteroids reduce duration of abdominal pain but do not prevent nephropathy 2
• For severe renal involvement, aggressive therapy with high-dose steroids plus immunosuppressants is recommended 1
• ACE inhibitors or ARBs should be considered for persistent proteinuria (>3 months) 2

ITP Management

• Treatment decisions based on bleeding risk rather than platelet count alone 5
• First-line therapies include:
  • IVIg (0.8-1 g/kg) - raises platelet count in >80% of patients within 1-2 days 5
  • IV anti-D immunoglobulin (50-75 μg/kg) for Rh(D)-positive patients 5
  • Corticosteroids (prednisone 1-2 mg/kg/day) for short-term use 5
• "Watch and wait" approach appropriate for many patients, especially children with mild symptoms 5
• Emergency treatment for life-threatening bleeding includes high-dose corticosteroids, IVIg, platelet transfusions, and possibly recombinant factor VIIa 5

Prognosis and Monitoring

HSP Prognosis

• Average duration of disease is 4 weeks 2
• Long-term prognosis depends primarily on renal involvement 1, 2
• End-stage renal disease occurs in 1-5% of patients 1
• Monitoring focuses on renal function with urinalysis and blood pressure checks 2

ITP Prognosis

• In children, spontaneous remission rates are high: 74% in children <1 year, 67% in ages 1-6, and 62% in ages 10-20 5
• Adult ITP more likely to become chronic with only 20-45% achieving complete remission by 6 months 5
• Mortality 1.3-2.2 times higher than general population due to bleeding, infection, and cardiovascular disease 5
• Regular monitoring of platelet counts and bleeding symptoms required 5

Special Considerations

HSP Special Considerations

• Renal involvement is the most important prognostic factor 2
• Treatment focuses on preventing complications rather than altering the disease course 1, 2
• Recurrence occurs in approximately 30% of cases 2

ITP Special Considerations

• Secondary causes (HIV, HCV, H. pylori) should be identified and treated 5
• Quality of life and fatigue are significant concerns, especially in the first year after diagnosis 5
• Activity restrictions may be necessary based on platelet count and bleeding risk 5
• Platelet transfusions generally ineffective except in emergency situations due to rapid destruction 5

Key Management Pitfalls to Avoid

• Do not confuse HSP's palpable purpura (with normal platelets) with ITP's purpura (with low platelets) 1, 5
• Avoid prolonged corticosteroid use in children with either condition due to serious side effects 5, 2
• Do not delay treatment of severe bleeding in ITP; emergency protocols should be initiated immediately 5
• In HSP, do not assume corticosteroids will prevent nephropathy, despite their benefit for abdominal and joint symptoms 2
• Avoid unnecessary bone marrow examinations in typical ITP presentations 5