Eosinophilia

Definition

• Eos. > 450/mcl
• Helminth infection most common cause in travellers/migrants
  • May be less prominent for migrants having dwelled in endemic area for long time
• May be the only sign without any symptoms

Cause

• Allergy/autoimmune
• Infection
• Neoplasm
• Drug
• Rare eosinophillic disorder
• Others

Infectious eosinophilia

• Helminth
  • when migrating to lung
  • tissue invasion
• Ectoparasites
  • scabies
  • myiasis
• Protozoa
  • Sarcocystis, Cystoisospora belli
• Resolving bacterial/viral infection
  • "Eosinophilic dawn" - no need to investigate
• Fungus
  • Coccidioidomycosis
  • Paracoccidioidomycosis
• HIV?
  • not by HIV itself? by superinfection?

History taking

• Where the patient stayed
  • migrantの場合は必ずしも居住地での感染に限らず，移住の過程で感染する可能性もある
• Time since return in travellers
• High or moderate or mild
  • mild eosinophilia may be from other than helminth
• What the patient was exposed with
  • freshwater
  • food, especially raw ones
  • barefoot walking
• Accompanying symptoms/signs

Test

• ova in stool
• helminthのserologyは交叉反応も多く信頼性が低い
  • ただしstronglyoides糞線虫は後の免疫抑制療法で致死的になるのでserologyでスクリーニングすべき
    • stronglyoides serologyが陽性になったら診断を頑張るよりivermectin単回投与で治療してしまえば良い
• "hypereosinophilia" > 1500/mcL suggests tissue and organ damage

Extent of eosinophilia

• stage of infection
• duration of infection
• tissue invasion
• immune responce