If you have a fever every night, there are usually several causes of the disease as follows: First, infectious factors, also known as inflammatory infections. There are usually bacterial, viral, fungal and atypical pathogens, such as mycoplasma or chlamydia infection resulting in fever is one of the most common clinical conditions. Common target organs such as respiratory tract infections, digestive system infections, urinary tract infections, pelvic or gynecological infections can trigger the production of the above mentioned fever. Second, non-infectious factors, for example, can also lead to fever every night. For example, the most common factors are immune system diseases and connective tissue diseases, such as dermatomyositis, systemic lupus erythematosus, rheumatism, rheumatoid arthritis, and tuberculosis, all of which can cause fever every night. Third, rare diseases such as hyperthyroidism and hyperadrenocorticism can also cause fever every night due to metabolic imbalance. Fourth, patients with immune deficiency, such as severe anemia and AIDS, tumors, etc., may also have fever every night.