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 management of Henoch-Schönlein Purpura (HSP) differs significantly from Immune Thrombocytopenic Purpura (ITP) due to their distinct pathophysiology, clinical manifestations, and treatment approaches.

Pathophysiology and Diagnosis

Henoch-Schönlein Purpura (HSP)

• HSP is an IgA-mediated systemic small-vessel vasculitis affecting the skin, gastrointestinal tract, joints, and kidneys 1, 2
• Diagnosis is based on palpable purpura with at least one of: diffuse abdominal pain, arthritis/arthralgia, or renal involvement (hematuria/proteinuria) 2
• Most cases occur in children 2-10 years of age, with peak incidence at 4-7 years 2
• Laboratory findings are usually normal, though rare cases may show low C3, mild leukopenia, and thrombocytopenia 3

Immune Thrombocytopenic Purpura (ITP)

• ITP is an acquired immune-mediated disorder characterized by isolated thrombocytopenia (platelet count <100 × 10⁹/L) without another obvious cause 4
• Diagnosis requires exclusion of other causes of thrombocytopenia 4
• Basic evaluation includes patient history, physical examination, complete blood count, reticulocyte count, and peripheral blood film 4
• ITP is classified by duration: newly diagnosed, persistent (3-12 months), and chronic (≥12 months) 4

Clinical Presentation Differences

HSP Presentation

• Characterized by a triad of palpable purpura (without thrombocytopenia), abdominal pain, and arthritis 1
• Over 90% develop purpuric rash, 75% develop arthritis, 60-65% develop abdominal pain, and 40-50% develop renal disease 1
• Purpuric rash typically appears on lower extremities 5
• Often preceded by upper respiratory infection 1

ITP Presentation

• Characterized by isolated thrombocytopenia with variable bleeding manifestations 4
• Many patients have minimal symptoms (bruising) while others experience serious bleeding (gastrointestinal, mucosal, or rarely intracranial hemorrhage) 4
• Platelet count correlates somewhat with bleeding risk, but additional factors like age and lifestyle affect risk 4
• In adults, ITP typically has an insidious onset without preceding illness and follows a chronic course 4
• In children, ITP is usually short-lived with two-thirds recovering spontaneously within 6 months 4

Treatment Approaches

HSP Management

• Most cases of HSP are self-limited and require only supportive care, with 94% of children and 89% of adults experiencing spontaneous resolution 1
• Oral prednisone (1-2 mg/kg daily for two weeks) may be used for abdominal and joint symptoms 1
• Corticosteroids reduce mean time to resolution of abdominal pain and may decrease odds of persistent renal disease in children 1
• For severe renal involvement, early aggressive therapy with high-dose steroids plus immunosuppressants is recommended 1
• For HSP nephritis with proteinuria >3 months, consider angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in addition to corticosteroids 2

ITP Management

• Treatment decisions are based on bleeding severity, platelet count, and patient factors 4
• First-line treatments in children include:
  • IV anti-D immunoglobulin for Rh(D)-positive children 4
  • IVIg (0.8-1 g/kg as single dose), which raises platelet count in >80% of children 4
  • Prednisone (1-2 mg/kg/day) or higher doses (4 mg/kg/day for 3-4 days) 4
  • Observation ("watch and wait") for approximately two-thirds of children who improve spontaneously 4
• For emergency treatment in life-threatening bleeding:
  • IVIg has the most rapid onset of action and should be considered with corticosteroids 4
  • Platelet transfusions may be given (often at higher than usual doses) 4
  • Recombinant factor VIIa has been used in some cases but carries thrombosis risk 4

Prognosis and Long-term Monitoring

HSP Prognosis

• Average duration of disease is 4 weeks 2
• Long-term prognosis depends primarily on severity of renal involvement 1, 2
• End-stage renal disease occurs in 1-5% of patients 1
• Long-term complications are rare and include persistent hypertension 2

ITP Prognosis

• In children, remission rates are age-related: 74% in children <1 year, 67% in those 1-6 years, and 62% in those 10-20 years (at 1 year) 4
• In adults, 20-45% achieve complete remission by 6 months 4
• Adults with ITP have 1.3-2.2-fold higher mortality than general population due to cardiovascular disease, infection, and bleeding 4
• ITP significantly impacts quality of life, particularly in the first year after diagnosis 4

Key Differences in Management

• HSP typically requires supportive care with short-term corticosteroids for symptomatic relief, while ITP often requires specific interventions to raise platelet counts 1, 4
• HSP treatment focuses on managing organ-specific manifestations (especially renal), while ITP treatment focuses on preventing and treating bleeding 1, 4
• HSP is usually self-limited with predictable course, while ITP may become chronic, especially in adults 1, 4
• Laboratory monitoring in HSP focuses on renal function, while ITP requires regular platelet count monitoring 1, 4
• HSP rarely involves thrombocytopenia, whereas ITP is defined by it 1, 4

Common Pitfalls and Caveats

• Do not confuse HSP's palpable purpura (with normal platelets) with the purpura of ITP (caused by thrombocytopenia) 1, 4
• Rare cases of HSP may present with thrombocytopenia, complicating the distinction 3
• Avoid prolonged corticosteroid treatment in children with ITP due to serious side effects 4
• In ITP, platelet count alone should not determine treatment; bleeding symptoms and patient factors are equally important 4
• Secondary causes of both conditions should be ruled out before confirming diagnosis 4, 2