Evaluation of Eosinophilia Presenting after Travel to Developing Countries
| Exclude nonparasitic causes of eosinophilia | Drug reaction, asthma, and urticaria; these are often apparent from history and during examination3 |
| Initial work-up | Stool samples for ova and parasites: at least 3 samples obtained from 3 different days |
| Should detect common parasitic causes, such as Ascaris and hookworm, and may detect Strongyloides and schistosomiasis, as well52 | |
| Serologies (per clinical and epidemiologic likelihood) | Often necessary for diagnosis of strongyloidiasis and schistsomiasis, and other, more rare parasitic causes of eosinophilia in returned travelers, such as cysticercosis, echinococcosis, toxocariasis, and trichinellosis, among others52 |
| Less useful for filariasis, in which marked eosinophilia is generally present only in the early stage of infection53 | |
| Fresh water exposure | Serology may not be positive until 3 months or more after exposure3 |
| Specificity 99% for all Schistosoma strains | |
| Sensitivity 99% for S. mansoni, but may be less than 50% for S. japonicum and S. hematobium | |
| Management of eosinophilia | Can be difficult to make a specific parasitic diagnosis |
| Schistosomiasis or strongly suspected schistosomiasis can be treated with praziquantel | |
| Often, nonschistosomal eosinophilia will resolve with an empiric 5 to 7 day course of albendazole, reflecting its generally helminthic nature52 | |
| Consultation with a tropical medicine specialist advised when aspects of diagnosis and management of eosinophilia are unclear |