Pediatrics · Year 3 · from Pediatrics

Case 3: Henoch-Schonlein Purpura

Patient Demographics

  • Age: 5-year-old male
  • Sex: Male

Chief Complaint

"He has a rash on his legs and is complaining of belly pain and sore knees."

History of Present Illness

A 5-year-old boy presents with a 3-day history of a rash on his legs that started on his ankles and spread upward to his buttocks. His mother initially thought they were bug bites, but the spots have not improved and appear raised. He has been complaining of abdominal pain for 2 days, crampy in nature, and he vomited once yesterday. He also reports pain in both knees and ankles, and the joints appear swollen. He had an upper respiratory infection about one week ago. He has had no fever, bloody stools, or difficulty breathing.

Physical Examination

  • Vital Signs: Temperature 37.4C, HR 96 bpm, RR 18/min, BP 98/62 mmHg
  • General: Alert, mildly uncomfortable-appearing boy
  • Skin:
  • Bilateral lower extremities: Palpable purpuric papules and macules, non-blanching, ranging from 2-10 mm, distributed symmetrically
  • Buttocks: Similar palpable purpura
  • Trunk and upper extremities: Spared
  • Abdomen: Diffuse mild tenderness, no rebound, normoactive bowel sounds
  • Musculoskeletal: Bilateral knee and ankle swelling with warmth; limited range of motion due to pain
  • Urinalysis: Trace blood, no protein (will need to follow)

Laboratory Findings

  • CBC: Platelets 385,000/uL (normal/elevated - rules out thrombocytopenic purpura)
  • PT/PTT: Normal (rules out coagulopathy)
  • Urinalysis: 1+ blood, no protein, no casts
  • BUN/Creatinine: Normal
  • Stool guaiac: Positive

Diagnosis

Henoch-Schonlein purpura (IgA vasculitis)

Clinical Reasoning

This child presents with the classic tetrad of HSP: (1) palpable purpura in a dependent distribution (lower extremities and buttocks), (2) arthritis/arthralgia affecting large joints, (3) abdominal pain with GI involvement (positive stool guaiac), and (4) renal involvement (microscopic hematuria). The normal platelet count distinguishes this from immune thrombocytopenic purpura. The rash is palpable (raised) because it represents small vessel vasculitis, not simple petechiae. The preceding upper respiratory infection is a common trigger. HSP is the most common systemic vasculitis in children, with peak incidence at ages 4-6 years.

Management

  1. Supportive care: Primary treatment for most cases
  2. NSAIDs: For arthralgia/arthritis (ibuprofen 10 mg/kg every 6-8 hours)
  3. Pain management: For abdominal pain; ensure adequate hydration
  4. Corticosteroids: Consider for severe abdominal pain (may reduce GI symptoms but do NOT prevent nephritis)
  5. Monitor for intussusception: Ileoileal intussusception can occur; obtain ultrasound if severe/worsening abdominal pain
  6. Renal monitoring: Urinalysis weekly for 1 month, then monthly for 3-6 months (nephritis may develop weeks later)
  7. Blood pressure monitoring: Hypertension may indicate significant renal involvement
  8. Prognosis: Excellent; most children recover completely within 4-6 weeks; recurrence in 30%

Clinical Image

Image Description: Bilateral lower extremities showing palpable purpuric papules characteristic of Henoch-Schonlein purpura (IgA vasculitis), with symmetric distribution and concentration in dependent areas.

Source: Wikimedia Commons - DermNet NZ URL: https://commons.wikimedia.org/wiki/File:Henoch-Schonlein_purpura.jpg License: CC BY-SA 4.0

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