Most of these symptoms are caused by viral and bacterial infections, mainly because the body’s resistance is relatively strong during the day, which inhibits the reproduction of viruses and bacteria, but at night the body’s resistance is weaker and viruses and bacteria reproduce more and more vigorously, making it easy to have a fever at night, but generally with a low fever. The fever is mainly low. When rheumatic immune diseases are present, this symptom may occur repeatedly, so it is necessary to go to the hospital for the corresponding examination. The majority of the rheumatic immune diseases need to be treated with regular glucocorticoid drugs under the guidance of a doctor.