Erythema Chronicum Migrans

Lyme Disease
Caused by the spirochete Borrelia burgdorferi, which is transmitted to humans by a deer tick bite, infection, is characterized by erythema migrans. A flat or slightly raised red lesion appears at the site. The reaction can become quite large, is generally circular in shape, and can show several concentric rings (target pattern). Erythema migrans is often accompanied by flu-like illness with fever, chills, and myalgias. At this stage, laboratory tests are not reliable.