Causes of an elevated eosinophil count include autoimmune diseases, allergies, skin disorders, tumors and endocrine disorders, notes Mayo Clinic. The medical term for an elevated eosinophil count is eosinphilia.
Eosinophilia results from over-production of eosinophils in the bone marrow or the accumulation of a large number of eosinophils at a specific location, states Mayo Clinic. Parasitic diseases, fungal infections and exposure to toxins are some additional causes of an elevated eosinophil count.
Eosinophils, a type of white blood cell, are activated when someone has an infection or allergic reaction, explains MedlinePlus. Some medications cause an increase in the number of eosinophils circulating in the blood, which can affect the results of the absolute eosinophil blood test. These medications include psyllium-containing laxatives, tranquilizers, amphetamines and certain antibiotics. A normal eosinophil level is less than 350 cells per microliter of blood.
Eosinophils play an important role in inflammatory processes, states Cincinnati Children's Hospital. The functions of eosinophils include trapping foreign substances, killing cells, modulating the inflammatory response, participating in allergic reactions, and fighting bacteria and parasites. It takes approximately eight days for new leukocytes to mature. Once they mature, they circulate in the blood for up to 12 hours before remaining at their destination sites for one to two weeks.