What are the signs, symptoms, and workup for Henoch-Schönlein Purpura (HSP)?

Henoch-Schönlein Purpura: Signs, Symptoms, and Workup

Clinical Presentation

HSP is characterized by a classic tetrad: palpable purpura (without thrombocytopenia), abdominal pain, arthritis/arthralgia, and renal involvement, with all patients developing purpuric rash and most having an antecedent upper respiratory infection. 1

Dermatologic Manifestations (100% of patients)

• Palpable purpura is the hallmark finding—non-blanchable, violaceous lesions caused by leukocytoclastic vasculitis 2, 1
• Distribution: predominantly affects bilateral lower extremities, particularly below the waist 3
• The rash represents bleeding underneath the skin from small vessel vasculitis, not thrombocytopenia 2
• Purpura may appear after other symptoms in some cases, making early diagnosis challenging 3, 4

Gastrointestinal Manifestations (60-65% of patients)

• Periumbilical and epigastric abdominal pain that worsens with meals due to bowel angina 1, 5
• Nausea, vomiting, and diarrhea (bloody or non-bloody) 3
• Hematemesis can be the initial presenting symptom, though uncommon 3
• Gastrointestinal bleeding—usually occult, less commonly melena 5
• Critical diagnostic pitfall: Abdominal symptoms may precede cutaneous lesions by days, making diagnosis extremely difficult 3, 4

Musculoskeletal Manifestations (75% of patients)

• Arthritis or arthralgia, typically affecting knees and ankles bilaterally 3, 1
• Joint involvement is usually self-limited 1

Renal Manifestations (40-50% of patients)

• Ranges from microscopic hematuria and mild proteinuria to nephritic/nephrotic syndrome 1, 6
• Acute kidney injury may occur 3
• Long-term prognosis depends entirely on severity of renal involvement—end-stage renal disease develops in 1-5% of patients 1

Diagnostic Workup

Essential Initial Laboratory Tests

• Complete blood count with peripheral smear: Normal platelet count (distinguishes from ITP), normal red and white cell morphology 7, 2
• Urinalysis: Assess for hematuria and proteinuria to detect renal involvement 1, 6
• Serum creatinine and BUN: Evaluate renal function 3
• C-reactive protein: Often elevated (inflammatory marker) 3

Confirmatory Testing

• Skin biopsy remains the gold standard for diagnosis 3, 1
  • Shows IgA deposition within walls of superficial dermal vessels 3
  • Demonstrates leukocytoclastic vasculitis with neutrophil infiltration and nuclear fragments 1, 5
  • Both H&E staining and direct immunofluorescence are required 2

Additional Workup When Gastrointestinal Symptoms Present

• Upper endoscopy if hematemesis or severe upper GI symptoms 3
  • May show erosive gastropathy, duodenitis, ulceration, or purpura 3, 5
  • Second portion of duodenum characteristically more involved than bulb 5
• Ultrasound is recommended as first diagnostic imaging test for abdominal pain 5
  • Detects intussusception (most common surgical complication, usually ileo-ileal or ileo-colic) 5
  • Shows asymmetric bowel wall thickening, mainly jejunum and ileum 5
• CT scan if ultrasound inconclusive or perforation suspected 5
• Intestinal biopsies during endoscopy show IgA deposition and leukocytoclastic vasculitis in submucosal vessels 5

Key Diagnostic Pitfalls to Avoid

• Do not exclude HSP based on normal platelet count—this distinguishes it from thrombocytopenic purpura 7, 2, 1
• Do not wait for rash to appear before considering HSP when abdominal pain and arthralgia are present—cutaneous lesions may be delayed 3, 4
• Always obtain skin biopsy when diagnosis uncertain, especially in adults who have higher complication rates 3, 1
• Screen for antecedent upper respiratory infection in history—present in over 90% of cases 1

Monitoring for Renal Complications

• Serial urinalysis and renal function tests are mandatory, as renal disease determines long-term prognosis 1, 6
• Persistent kidney disease can develop at 1,3,6, and 12 months after presentation 6
• Adults have higher risk of complications than children and require closer monitoring 1