Differential diagnostic search for hypereosinophilic syndrome

Idiopathic hypereosinophilic syndrome is characterized by a persistent increase in serum eosinophil counts >1.5 × 109 / L for 4 weeks and the absence of any clinical, laboratory and instrumental data suggesting the etiology of this phenomenon. It is not always possible to confirm the reactive nature of eosinophilia or identify clonal disease. The article presents a clinical case of differential diagnostic search for the cause of hypereosinophilia in a patient.