Headache and low fever in the fifties may be caused by systemic diseases or intracranial diseases. 1. Systemic diseases: for example, colds and other cold air stimulation by the outside world, may have an impact on the body, inducing cold and flu disease. After suffering from cold, it is very likely to affect the body, causing headache and low fever and other symptoms. 2. Intracranial diseases: such as encephalitis, patients with brain stimulation by physical and chemical factors or infections, can induce inflammation, so that patients with headaches and low fever symptoms, if not treated in time, low fever can turn into high fever. Fifty-something headache and low fever may also be caused by other reasons, the patient should go to the hospital in a timely manner, under the guidance of the doctor to carry out relevant examinations and treatment.