Eosinophils are a type of white blood cell. They help fight off infections and play a role in your bodys immune response. They can also build up and cause inflammation. Normally your blood doesnt have a large number of eosinophils. Your body may produce more of them in response to - Allergic disorders - Skin conditions - Parasitic and fungal infections - Autoimmune diseases - Some cancers - Bone marrow disorders In some conditions, the eosinophils can move outside the bloodstream and build up in organs and tissues. Treatment of the problem depends on the cause. 
What is (are) Eosinophilic Disorders ?