prodrome

an early non-specific symptom (or set of symptoms) indicating the start of a disease before specific symptoms occur. For example fever, malaise, headache and anorexia (lack of desire to eat) are part of the prodrome for mumps or a variety of infective disorders. A prodrome can be the precursor to the onset of a chronic neurological disorder such as migraine or epilepsy, where prodrome symptoms include scotoma, disorientation, aphasia, or photosensitivity