How does Lyme disease present?

The classic presentation is that of a person—in spring or early summer, living in an endemic area—with a history of a tick bite associated with fever and an annular, spreading rash called erythema chronicum migrans. Unfortunately, not all components are always present. As many as 50% of people with Lyme disease never develop the important sign of erythema chronicum migrans, and another 50% of the people do not recall a tick bite.

In addition to constitutional symptoms of general malaise, aches and pains, and fever, the disease may be complicated by cardiac, neurologic, and arthritic symptoms. Treatment in the early phase consists of antibiotics such as amoxicillin, erythromycin, or, most likely, doxycycline for a 3-week period of time. If Lyme disease progresses on to a more chronic problem, or there is evidence of neurologic symptoms, it is often necessary to use ceftriaxone in order to cross the blood–brain barrier.