Eosinophilia
The differential diagnosis of eosinophilia is vast, but helminth infections are a very common cause of eosinophilia in refugee patients and should be ruled out first before investigating other etiologies (unless the clinical presentation suggests another cause).
Our step-wise approach for refugee patients with eosinophilia:
Strongyloides and schistosoma serologies should have already been ordered as part of the initial screening tests. Treat if positive (see Strongyloidiasis and Schistosomiasis), and follow-up with a repeat CBC at least 4 weeks later to reassess the eosinophil count. If the eosinophilia is still present, another cause should then be considered. In patients with a positive schistosoma serology who have persistent eosinophilia after the initial praziquantel dose, it is reasonable to treat them a second time since a single dose might not be sufficient to kill all the worms.
Order at least 3 serial stool Ova & Parasites examinations to look for other potential helminth infections (mainly hookworms and flukes). Stool microscopy is not a sensitive test and repeat testing is thus recommended to increase the sensitivity. However, based on our experience with our refugee patients, it is often difficult to obtain a proper stool sample to perform this test. In these cases, it is reasonable and safe to simply treat empirically for helminth infections with mebendazole (500 mg once, or 100 mg twice daily for 3 days - for patients ≥ 2 years of age). See Gastrointestinal Parasites for the treatment of common gastrointestinal parasites.
If the initial serologies and stool examinations did not reveal any helminth infection, then other parasitic causes such as trichinella, filariae, flukes and toxocara (mainly in children) should be ruled out. These investigations should however be ordered by an Infectious Diseases specialist.
The non-infectious causes of eosinophilia should also be considered (especially if the parasitic work-up is negative): medication-related eosinophilia, asthma/atopic disease, hematologic diseases, vasculitis (Churg-Strauss syndrome), diseases with specific organ involvement (skin, lungs, gastrointestinal tract, heart…), etc. The following basic investigations can be ordered as a first step: peripheral blood smear, electrolytes, creatinine, urinalysis, B12 levels, liver function tests, troponin, and chest X-ray. The complete work-up for these potential causes is however outside the scope of this resource. |