Recent advances in the classification and management of hypereosinophilia

Abstract

Numerous disorders and etiologies may underlie increased eosinophil counts. Hypereosinophilia (HE) is defined as a peripheral blood eosinophil count greater than 1,500/mm and may be potentially harmful because of tissue damage. Hypereosinophilic syndrome (HES) also represents a heterogeneous disorder characterized by persistent HE with the evidence of organ dysfunction, clinical symptoms, or both caused by eosinophilia. The refining criteria and subclassification of HE and HES are currently being revised on cellular and molecular based diagnostic methods. Initial approaches focus on evaluating various underlying causes, including helminthic infections, adverse drug reactions, allergic diseases, and neoplastic diseases. When secondary causes of HE are excluded, the workup should proceed to the evaluation of primary/clonal bone marrow disease, including fip 1-like 1-platelet driven growth factor receptor alpha (FIP1L1-PDGFRA) mutation. Concurrently, if the patient has symptoms and signs, organ damage or dysfunction must be evaluated. Although, corticosteroids are the mainstay of therapy in confirmed HES, imatinib is considered a definitive treatment for FIP1L1-PDGFRA, platelet driven growth factor receptor beta rearranged HE and HES. In this article, we discuss recent advances in the classification of and practical approaches to HE and HES. In addition, we introduce several promising therapies for HE and HES. (Allergy Asthma Respir Dis 2015;3:387-395)