The severity of a patient’s eosinophilic condition needs to be evaluated on a disease-specific basis. Allergic asthma and atopic dermatitis have a more acute onset, while parasitic infections and primary eosinophilia have a slower onset, but are equally important and require prompt treatment. Eosinophilia can be categorized into the more common secondary, and primary conditions: 1. The causes of eosinophilia include allergic asthma, atopic dermatitis and other allergic diseases, as well as parasitic infections, etc. Most of these patients show mild to moderate eosinophilia, which is secondary to elevated eosinophilia, and the eosinophilia can gradually return to normal after the primary disease is cured. In severe cases, allergic asthma can lead to severe respiratory distress, which can be life-threatening if not treated in time. Therefore, patients with elevated eosinophils due to allergic asthma should standardize their treatment and prevent asthma attacks. 2. Primary eosinophilia and other hematologic diseases can also lead to elevated eosinophils, often with a gradual increase, which is relatively rare in these patients. This kind of patients is relatively rare. If the disease is serious, it can affect the respiratory function of the patients, dexamethasone, prednisone and other glucocorticosteroids are effective in the treatment, and it is recommended that the patients go to the hematology department in time for consultation and treatment.