Lyme disease begins several days or a few weeks after the tick bite. The patient complains of typical upper expiratory infection symptoms such as headache, fatigue, muscle and joint pains and a low-grade fever. A distinctive rash called erythema migrans occurs in up to 75% of patients. In some instances the rash begins at the bite site.
Untreated patients either develop an immune response and clear the disease or go on to a second or third stage that involves the nervous system, joints and the heart. These are the same organs involved in the third stage of syphilis (tertiary syphilis).