Headache with fever should be identified as a result of blood tests plus C-reactive protein and, if necessary, chest X-ray or chest CT to check whether it is caused by bacterial or viral, fungal or atypical pathogenic infections. 1. Inflammatory infections cause 70%-80% of headache with fever, and all the above-mentioned inflammatory diseases can cause headache with clinical fever, such as respiratory tract infections, digestive system infections, urinary tract infections, peritoneal infections and pelvic infections. 2. Inflammatory diseases such as non-bacterial infections can also cause headache with fever, for example, immune system diseases, connective tissue diseases, rheumatic fever, rheumatoid arthritis, dermatomyositis, and systemic lupus erythematosus all have headache with fever. The above symptoms.