There are many kinds of diseases that cause fever, and there are several major clinical categories: 1. Infectious diseases, commonly tonsillitis, otitis media, pharyngitis, bronchopneumonia, tuberculosis, bronchiectasis, peritonitis, urinary tract infections, skin infections, etc. 2. Hematologic diseases, acute leukemia, chronic leukemia, lymphoma may cause fever. 3. Rheumatic immunologic diseases, commonly mixed Connective tissue disease, dermatomyositis, systemic lupus erythematosus, rheumatoid arthritis, rheumatoid arthritis, can also cause fever. 4, endocrine diseases, common hyperthyroidism. 5, tumors, various malignant tumors can cause fever.