A multisystem disease characterized by necrotizing granulomatous vasculitis with eosinophilia that most commonly involves the lungs and the skin; can also affect the renal, cardiovascular, gastrointestinal, central, and peripheral nervous systems

Epidemiology

Etiology

Pathophysiology

Clinical features

• Prodromal phase
  • Severe allergic asthma attacks (chief concern)
  • Allergic rhinitis/sinusitis
• Eosinophilic phase
  • Lung disease
  • Pericarditis
  • Gastrointestinal involvement: bleeding, ischemia, perforation
• Vasculitic phase
  • Skin nodules, palpable purpura
  • Mononeuritis multiplex (loss of motor and sensory function with wrist or foot drop), symmetric or asymmetric polyneuropathy
  • Pauci-immune glomerulonephritis

Diagnostics

• CBC: peripheral blood eosinophilia (> 1500 cells/mcL or > 10% of the leukocyte count)
• ANCA present in ∼ 40%: of those, MPO-ANCA in 74–90%
• ↑ IgE and ↑ IgG4 levels

Treatment