Clinical Features

  • Lungs
    • Asthma - cardinal feature (95%), often severe or steroid-dependent, with steroids often masking other signs of disease
    • Other findings (in 50-70%): pulmonary opacities with eosinophilia, pleural effusion (often eosinophilic), nodules that are rarely cavitary, alveolar hemorrhage
  • Upper airway
    • Allergic rhinitis, chronic rhinosinusitis with nasal polyps
    • Chronic serous otitis and sensorineural hearing loss are occasionally seen in CSS and likely reflect the severity of sinusitis (necrotizing lesions as with Wegener's is unusual)
  • Skin
    • Tender subcutaneous (granulomatous) nodules on the extensor surfaces of the arm, particularly the elbows, hands, and legs occur in up to 2/3rds of patients during the vasculitic phase
    • Skin lesions can also appear as palpable purpura, a macular or papular erythematous rash, and hemorrhagic lesions, ranging from petechiae to extensive ecchymosis
  • Other
    • CV - heart failure, effusion, valvular abnormalities, arrhythmia
    • CNS - peripheral neuropathy
    • Renal - renal insufficiency, glomerulonephritis
    • GI - eosinophilic gastroenteritis

Usually occurs in sequential phases
  • Late-onset asthma and allergic rhinitis
  • Very rarely occurs in children

  • Blood eosinophilia, eosinophilic infiltration of lungs, GI tract, skin, and other organs
  • 40% may progress to vasculitic phase
  • Life-threatening systemic vasculitis of small-medium vessels
  • Often accompanied by skin findings and constitutional symptoms (fever, weight loss, fatigue)
  • Cardiac symptoms are cause of death in 50%


American College of Rheumatology Criteria (1990) - a patient shall be said to have CSS if at least 4/6 criteria are positive (sensitivity 85%/specificity 99.7%)
  • Asthma
  • Blood eosinophilia >10%
  • Neuropathy, mono or poly
  • Pulmonary infiltrates, non-fixed
  • Paranasal sinus abnormality
  • Extravascular eosinophils on blood vessel biopsy

  • Laboratory tests
    • Eosinophilia - usually 5000-9000, but >1500 or 10% should prompt suspicion; often suppressed by systemic steroids
    • ANCA - found in 40-60% of patients; majority (70-75%) of ANCA positive will have MPO-ANCA or pANCA
      • Negative ANCA may correlate with different natural course of CSS
    • Nonspecific abnormalities:
  • Imaging
    • CXR - often demonstrate diverse findings
      • Usually transient and patchy opacities (75%) without lobar or segmental distribution
      • Pleural effusions (30%) are usually exudative and eosinophilic
    • HRCT - typical findings include patchy parenchymal consolidation or ground glass opacification, nodules may also be noted
  • Other: PFTs, bronchoscopy/BAL, surgical biopsy of involved skin/nerve/lung site, EKG, echocardiogram, cardiac MRI

Differential Diagnosis

  • AERD - may overlap clinically with prodromal phase of CSS
  • ABPA - only affects sinopulmonary sites
  • Eosinophilic pneumonia - usually isolated to lungs, usually lack granulomas on biopsy
  • Hypereosinophilic syndrome
  • Wegener's granulomatosis - usually not associated with marked eosinophilia and asthma, and ANCA is typically anti-PR3 (cANCA)
  • Microscopic polyangiitis - usually not associated with marked eosinophilia and asthma