Erythema migrans is the distinctive cutaneous marker of
Lyme borreliosis. The clinical picture is variable but at some point in its evolution, erythema migrans presents as a red, centrifugally expanding, annular plaque. Erythema migrans may appear as a solitary lesion or in multiplicity. It may be accompanied by extra cutaneous signs and symptoms as fever, headache, musculoskeletal discomfort, and regional lymphadenopathy. The diagnosis of erythema migrans is based primarily on clinical findings because serologic tests to detect elevated antibody levels to Borrelia burgdorferi are frequently negative during the first few weeks of the illness. Identification of Borrelia burgdorferi from skin biopsy specimens obtained from erythema migrans lesions microbiologically or histopathologically will confirm the clinical diagnosis of erythema migrans.