Cause and incidence of eosinophilia in children: a single center study in one year

ABSTRACT

PURPOSE: Eosinophilia may be associated with various primary and reactive conditions. However, studies on the cause and incidence of eosinophilia in Korean children are rare. This study aimed to evaluate the cause and incidence of eosinophilia in patients at a single university hospital. METHODS: We studied 8,285 pediatric patients under the age of 18 years who had eosinophilia at Pusan National University Hospital. Premature and newborn infants were excluded. Eosinophilia was defined as an absolute eosinophil count greater than 450/microL. Eosinophilia was categorized as mild (450-1,500/microL), moderate (1,500-5,000/microL), and severe (>5,000/microL). The underlying conditions of eosinophilia were retrospectively investigated. RESULTS: Of 8,285 patients who had a hematology profile, 497 (5.9%) were found to have eosinophilia. Of patients with eosinophilia, 333 patients (67.0%) had identifiable and possible causes. The major causes of eosinophilia were allergic diseases (61.3%), infectious diseases (19.8%), immunologic diseases (9.0%) and hemato-oncologic disease (5.1%). Immunological disease such as Idiopathic hypereosinophilic syndrome, drug induced hypersensitivity syndrome and Graft-versus-host disease was the common condition with moderate to severe eosinophilia in which eosinophil count in peripheral blood was more than 1,500/microL. CONCLUSION: The most common cause of eosinophilia was allergic disease. Immunological disease was the common condition with moderate to severe eosinophilia.