Eosinophils are a type of white blood cell and are divided into two types: granulocytes and granulocytes, granulocytes contain special staining granules. If eosinophilia is abnormal, it is considered to be due to an allergic reaction, such as food allergies or hives, allergic pneumonitis, certain skin diseases, such as mycosis fungoides or psoriasis, eczema, herpes-like dermatitis. If eosinophilia is decreased, there may be parainjury or typhoid fever and other infections in the early stages, or stress and the application of glucocorticoids.