Eosinophilia

Background

• Any eosinophil count over 0.5
• May be primary (either eosinophilic hematologic malignancy or idiopathic) or secondary/reactive

Differential Diagnosis

• Hematologic
  • Primary: eosinophilic leukemia, CMML, hypereosinophilic syndrome
  • Secondary: Non-Hodgkin lymphoma and Hodgkin lymphoma
• Infectious
  • Parasitic infections including Strongyloides stercoralis, hookworms, schistosomiasis, and scabies
  • Tropical pulmonary eosinophilia from filarial roundworms (Wuchereria bancrofti and Brugia)
  • Can also be seen with other helminths, HIV, HTLV, Borrelia, and Aspergillus
• Inflammatory
  • Eosinophilic pneumonia
  • Eosinophilic esophagitis
  • Eosinophilic myositis
  • Eosinophilic granulomatosis with polyantiitis (eGPA or Churg-Strauss)
• Endocrine
  • Addison disease
• Allergy
  • Atopy
  • Asthma
  • Drugs
    • Hypersensitivity reaction to NSAIDs, antibiotics, allopurinol, aromatic anticonvulsants, sulfasalazine, TMP-SMX, PPIs, vancomycin
    • Drug reaction with eosinophilia and systemic symptoms (DRESS)

Investigations

• CBC
• Stool for ova and parasites (specifically for helminths rather than protozoa)
• Strongyloides serology, +/- Schistosoma serology
• ANCAs
• Review current medications