Children who have a fever for a while and then don’t are usually associated with infectious diseases such as bacterial infections and viral infections, but may also be associated with non-inflammatory diseases and other factors. 1. Infectious diseases: (1) Bacterial infections: mainly including cocci, bacilli, etc. If there are bacteria in the body, repeated stimulation of the human organism will lead to a decline in immunity, which will cause fever and fever, and the temperature may go up for a while and down for a while. (2) Viral infections: for example, herpes virus, influenza virus, adenovirus, etc. Repeated stimulation of the human organism will lead to a rise in temperature, but the virus is not cleared from the body, and there may be a sudden rise in temperature and a sudden fall. 2. Non-inflammatory diseases: for example, common connective tissue diseases, leukemia, etc., may appear body fever, fever and other conditions, and will lead to body temperature a moment to rise a moment to reduce. Children who have fever for a while, but not for a while, should also be suspected of encephalitis and other diseases, it is recommended to confirm the diagnosis and analyze the cause of the disease under the guidance of a professional physician.