Illness begins days to 1 month after tick bite. A red macule or papule arises at the tick bite site, which expands centrifugally to form an annular erythematous lesion. B. burgdorferi proliferation and the host’s immune reaction eventually produce the characteristic skin lesion, erythema migrans (EM) in about 80% of U.S. cases (40% in Europe). EM is the best clinical marker for Lyme disease. A photo of someone with Lyme disease can be found at http://www.cdc.gov/ncidod/dvbid/lyme/diagnosis.htm

Adapted from: Goldstein MA and Harden CL. Infectious states. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;83-133.
With permission from Elsevier (www.elsevier.com).
Reviewed and revised March 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.