Abstract: Idiopathic hypereosinophilic syndrome (IHES) is a very rare disorder in children, characterized by increased eosinophils in bone marrow, peripheral blood and tissue, resulting in multiple organ damage. We report a case of an 8-yearold girl with IHES, whose initial complaints were diarrhea and abdominal distension. Image examinations indicated that the digestive tract, lung and urinary bladder were all affected. Routine blood test showed that the eosinophilia was 20.64×109/L. Bone marrow smear showed that the mature eosinophilic granulocytes increased to 32%. The FIL1P1/PDGFRA, FGFR1 and IGH gene detection, parasites and antibody tests were all negative. The diagnosis of IHES was considered. The eosinophil decreased significantly and symptoms relieved after steroid treatment, though with recurrences, steroids were still sensitive. Then we reviewed the relevant literature and cases of children with IHES in China.

Key words: rare diseases, hypereosinophilic syndrome, idiopathic, child