It is not normal for children to have fever every few days, and this situation should be promptly consulted, alert to the symptoms of certain diseases, such as infections, connective tissue diseases, immunodeficiency diseases and other diseases. 1. Infection: when the child’s body is infected by pathogenic microorganisms, pathogenic microbial metabolites or their toxins can act on the leukocytes and produce endogenous pyrogen, the child can be accompanied by chills, fever, chills, dizziness, headache, fatigue, muscle aches and other systemic symptoms. 2. Connective tissue diseases: such as vasculitis, systemic lupus erythematosus, etc., the autoantigen-antibody immune response can cause fever, but also may appear weakness, fatigue, diarrhea, abdominal pain and other symptoms. 3. Immunodeficiency disease: a systemic disease caused by underdevelopment or damage to the immune system, often with unexplained fever, accompanied by malaise, weakness, anemia, malnutrition, mental laxity, delayed growth and development. It is difficult to diagnose by this symptom alone. There are many causes of fever in children, and other factors cannot be excluded. It is recommended that parents should bring their children to the doctor in time, ask the doctor to clarify the cause and give targeted treatment.