Chills before fever may be caused by early acute infectious diseases, infectious diseases, reactive diseases, non-infectious diseases and so on. 1. Early stage of acute infectious diseases: common infectious diseases such as typhoid fever, malaria, acute cornual tuberculosis and so on, in the early stage of the disease, may lead to the symptoms of chills before fever. 2. Infectious diseases: If you suffer from acute respiratory infections, usually caused by bacterial or viral infections, when the pathogen invades the body in the acute stage, it may lead to chills before fever. 3. Reactive diseases: for example, acute allergy, post-vaccination reaction, blood transfusion reaction, etc., all of which may lead to chills before the onset of fever. 4. Non-infectious diseases: malignant tumors, systemic lupus erythematosus, intracranial injuries and other non-infectious diseases are common, and chills may also appear before fever. When the patient has the symptoms of chills before fever, he should consult a doctor in time to avoid delaying his condition.