Objective: We assessed the frequency of parasitic diseases and the efficacy of presumptive treatment when no cause was found.
Materials and methods: This prospective study took place in the Tropical Disease department of Bicêtre Hospital over a two-year period and included patients with eosinophil counts exceeding 500/mm(3).
Results: The study included 117 patients with blood eosinophilia. A parasitic infection was identified for 48 (41%), and appropriate treatment resulted in a return to normal eosinophil counts for all of them. No parasite was identified in 45 patients (38.5%), but parasitic disease was suspected on the basis of clinical or epidemiologic evidence. These patients received presumptive treatment with antiparasitic drugs (ivermectin, albendazole and praziquantel, alone or in combination). Of the 30 patients in this group not lost to follow-up, eosinophil counts returned to normal for 20. Finally, a cause other than parasitosis was suspected for 15 of the 117 patients (13%): 9 (7.5%) of them were lost to follow-up.
Discussion: Parasites remain the leading cause of blood eosinophilia. Because the sensitivity of additional testing for these parasites is low and these antiparasitic drugs are safe (except for patients with loiasis), presumptive treatment appears appropriate.