Eosinophils are specialized white blood cells that participate in inflammatory processes such as allergic diseases. They also are involved in tissue repair and remodeling.
In healthy people, eosinophils comprise approximately 1 to 6 percent of white blood cells. The body may produce more of these cells in response to parasitic and fungal infections. Certain allergic diseases, skin conditions, autoimmune disorders, cancers, and bone marrow diseases also may result in elevated eosinophil counts. Many people with eosinophilic disorders have high numbers of eosinophils in their blood or tissues over a long period of time. Sometimes, the presence of excess eosinophils in tissue, called “eosinophilic inflammation,” can result in tissue damage.