Epidemiology

• History: first described by Dr. William Heberden in London in 1801
  • Johann Schönlein (1837) and Edouard Henoch (1874) reported additional cases decades later
• Predisposing Factors: preceding URI occurs in 66% of cases
• Peak age: infancy/childhood (mean age: 5.9 y/o)
  • However, can occur at any age: generally more severe in adults
  • >90% of cases occur in children
• Henoch-Schonlein Purpura is the most common form of vasculitis in children
• Annual Incidence: 140 cases/million persons

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Physiology

• Hypersensitivity vasculitis (mostly involving the post-capillary venules within superficial dermis) with leukocytoclasis
• Probably due to immune complex deposition in response to an infection
  • Probably due to IgA immune complexes

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Pathology

• Pathology with Diffuse Alveolar Hemorrhage: pulmonary capillaritis (see Wegener’s above)
• IgA immune complexes have been seen in the alveolar septa

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Diagnosis

• Serology:
  • ANA: negative
  • Anti-DNA: negative
  • RF: negative
  • C3/C4/CH50: normal
  • ANCA: variable
  • Anti-GBM: negative
  • Immune complexes (with IgA): positive
• PFT’s:
  • Decreased DLCO: in cases with interstitial infiltrates
  • Increased DLCO: during active diffuse alveolar hemorrhage
• ABG: elevated A-a gradient
• U/A: abnormal
• CXR/CT Patterns
  • Pleural effusion
  • Diffuse or patchy perihilar/alveolar infiltrates: may be trasient
    -Interstitial infiltrates: may appear with chronic or recurrent diffuse alveolar hemorrhage
• OLB: may be necessary
  • Tissue Ab staining: granular pattern (IgA) in alveolar septa
• Skin Bx: diagnostic (IgA deposition)
• Renal Bx: focal segmental necrotizing glomerulonephritis, crescents
  • IgA deposition
• FOB:
  • BAL: RBC’s/ hemosiderin-laden macrophages

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Clinical

Dermatologic Involvement

• Lekocytoclastic Vasculitis: palpable purpura (of LE), nodules, ulcers

Renal Involvement

(only 5% of cases develop progressive chronic kidney disease)

• Glomerulonephritis/Renal Failure
• Hematuria

Pulmonary Involvement (rare)

• Diffuse Alveolar Hemorrhage (see [[Diffuse Alveolar Hemorrhage]])
  • Hemoptysis
  • Cough
  • Dyspnea
  • Chest Pain
• Lung Cancer (squamous cell) (see [[Lung Cancer]])

Rheumatologic Involvement

• Polyarthralgias (without arthritis)

GI Involvement

• Abdominal Pain

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Treatment

• NSAID’s: avoid in presence of renal and GI disease, as may excerbate these
• Dapsone (100 mg/day) : may be effective
• Corticosteroids: effective in treating joint and GI symptoms
  • Not effective in treating skin symptoms: skin symptoms usually resolve spontaneously though

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Prognosis

• Usually self-limited: resoledv within a few weeks
• Recurrences occur in 33% of patients: recurrence usually develops within the first few months after resolution of the first episode

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References

• The American College of Rheumatology 1990 criteria for the classification of Henoch-Schönlein purpura. Arthritis Rheum. 1990 Aug;33(8):1114-21