The premonitory or precursor symptoms of a disease, especially a communicable disease. In the case of communicable diseases that present clinically with a skin rash, prodromal symptoms are those usually preceding the appearance of the rash. For example, the characteristic skin rash of measles is preceded by prodromal symptoms that include fever, cough, inflamed conjunctivae, and Koplik spots. The prodromal period varies widely according to the natural history of the particular disease, from a few hours or less to many months.
Subjects: Public Health and Epidemiology.