ObjectiveTo explore the clinical characteristics of idiopathic hypereosinophilic syndrome (IHES), and improve the early diagnosis and treatment of such diseases.MethodsThe clinical diagnosis and treatment data were retrospectively analyzed from the patients with confirmed IHES hospitalized in China-Japan Friendship Hospital between September 2010 to May 2018.ResultsFifteen patients were included. There were 3 women and 12 men in the study, with an average age of 53.7±21.3 years. Eleven patients had respiratory problems, with an average course of 7 months. Most lesions occurred in both lungs. Patchy distribution, ground glass opacity, pleural effusion and mediastinal lymph node enlargement were common in the chest computed tomography. Serum total IgE was significantly increased. Four patients had other systems involved rather than respiratory system. One of them had digestive problems and another 3 had skin diseases. There was a significant increase in eosinophils in peripheral blood, bone marrow and histopathology, the same as eosinophils in sputum, pleural effusion, and bronchoalveolar lavage fluid. Hypoxemia was common in patients with respiratory problems. The blood eosinophil and total IgE were reduced after glucocorticoid treatment, and the hypoxemia was significantly improved.ConclusionsThe clinical symptoms, signs and image of chest computed tomography are not specific in IHES, so the rate of misdiagnosis and wrong diagnosis is high. This disease involves many organs or systems, so the pathological examination should be completed as soon as possible to make a clear diagnosis to prevent further damage. Glucocorticoid treatment is effective in this disease.