The Lack of Association of Eosinophilia and Neurocysticercosis at Clinical Presentation: A Retrospective Analysis of Cases Seen at the National Institutes of Health, 1985-2015.

Eosinophilia is a common laboratory finding in helminth infections but whether it is suggestive of neurocysticercosis (NCC) is controversial and inadequately studied. We determined the presence of eosinophilia (≥ 500 eosinophils/mm3) at clinical presentation in 72 patients with a proven or probable diagnosis of NCC and who had not received corticosteroids within 2 weeks of evaluation and complete blood count. Only two persons whose last possible endemic exposures to NCC were 7 and 6 years earlier had eosinophilia of 500 eosinophils/mm3 and both had a positive antibody serology to strongyloidiasis. In the one subject where a follow-up assessment was possible, the eosinophilia resolved. The likely cause for eosinophilia in both was strongyloidiasis. Therefore, none of the subjects with newly diagnosed NCC had significant eosinophilia. Eosinophilia in newly diagnosed symptomatic NCC subjects who had remote exposure is unusual and should prompt a search for another process or infection.