Hypereosinophilic Syndrome: diagnostic advances, therapeutic approaches, and clinical perspectives

Abstract

Hypereosinophilic syndrome (HES) is a heterogeneous group of disorders characterized by persistent eosinophilia and related tissue damage. Eosinophilia is defined by peripheral blood eosinophil counts above 1,500 cells/µL for an extended period, typically longer than six months, in the absence of secondary causes such as parasitic infections or allergies. HES may affect multiple organs, including the heart, lungs, skin, central nervous system, and gastrointestinal tract, leading to diverse clinical manifestations. The pathophysiology involves both reactive and neoplastic mechanisms, and specific genetic mutations, such as FIP1L1-PDGFRA, can be identified in some subtypes. Diagnosis requires comprehensive evaluation to exclude secondary causes and identify specific variants, directly influencing treatment. Therapy includes corticosteroids, cytotoxic agents, and targeted therapies like tyrosine kinase inhibitors. Prognosis varies according to disease form and treatment response, and multidisciplinary follow-up is essential. Recent advances in molecular biology have enabled better stratification and personalized management. HES remains a diagnostic and therapeutic challenge, requiring greater medical awareness and ongoing investigation.