Eosinophilia and cystic echinococcosis: what is the relationship?

Cystic echinococcosis (CE) is a chronic, complex and neglected zoonotic disease caused by Echinococcus granulosus. Eosinophilia in CE is a classic analytic alteration, although its presentation and importance is very variable and not well established.

We performed a retrospective observational study of inpatients diagnosed with CE and eosinophilia from January 1998 to December 2017 in the Complejo Asistencial Universitario de Salamanca in western Spain.

During the study period, 475 patients with a CE diagnosis underwent a haemogram and 118 (24.8%) patients had eosinophilia. Eighty-two (69.5%) were male and the mean age was 52.1±20.8 y, which was younger in the group with eosinophilia (p<0.001). The patients with eosinophilia had less comorbidity (33.1% vs 52.9%; p<0.001) and they were diagnosed with more complications (60.2% vs 39.8% asymptomatic; p<0.001). Clinical manifestations appeared in 71 cases (60.2%). The eosinophilia was related to the presence of pre-surgical fistulas (p=0.005). We observed significant differences when considering whether eosinophilia is a marker of the type of treatment (p<0.001).

Eosinophilia can be an indicator for an active search in CE because as much as 40% of cases are asymptomatic at diagnosis. In patients with eosinophilia, management is usually more aggressive and is usually a combined treatment. Our work shows the importance of eosinophilia in our patients with CE and raises unresolved questions.