1 Introduction Hypereosinophilic syndromes (HES) are a heterogeneous group of rare disorders characterised by persistent eosinophilia and organ damage due to eosinophilic infiltration. Idiopathic HES (I-HES) is diagnosed when secondary causes of eosinophilia (parasitic, fungal or mycobacterial infection, allergies, irradiation, toxins, connective tissue diseases or neoplasia) and primary bone marrow disorders have been excluded [1]. Respiratory manifestations are common in HES patients.