Eosinophils are one kind of white blood cells, which have important physiological functions such as immunity and phagocytosis, and the causes of high eosinophils include allergic diseases, parasitic infections, skin diseases, blood diseases, infectious diseases and so on. 1. Allergic diseases Such as bronchial asthma, allergic purpura, allergy, etc.. When the allergic reaction occurs, the cell produces interleukin secretion increases, interleukin increases to activate specific IgE production, when the allergen enters the body again, so that the cell releases eosinophilic cells to increase, thus occurring eosinophilic high situation. 2. Parasitic infections Such as schistosomiasis and roundworm disease. There are eosinophils, plasma cells and macrophages infiltrating around the worm body and eggs. Patients may show fever, hepatosplenomegaly, and high eosinophilic granulocytes. 3. Skin diseases Such as dermatitis, acne, etc., due to various skin diseases causing itching, redness, pimples, etc., or secondary infection, causing intense itching, inflammation, etc., resulting in high eosinophils. 4. Blood diseases Such as chronic granulocytic leukemia, eosinophilic granulocytic leukemia, lymphoma and so on. Due to the abnormal hematopoietic function of bone marrow, the secretion of leukocytes increases, and leads to high eosinophil. 5. Infectious diseases For example, scarlet fever, when streptococcus adheres to mucosal epithelial cells, inducing tissue inflammation, bacterial pods resist phagocytosis by eosinophils, which can also lead to high eosinophils. It is recommended that patients with high eosinophil percentages seek medical attention in a timely manner, under the guidance of a physician to clarify the diagnosis and receive treatment.