What Does the Rash of Lyme Disease (Erythema Migrans) Look Like?
A key component of early diagnosis is recognition of the characteristic Lyme disease rash called erythema migrans (EM). This develops at the site of the tick bite in about 80% of Lyme disease patients about 3 to 30 days following the tick bite. Typically, the rash expands over a period of several days, reaching up to 12 inches (30 cm) across. The center of the rash may clear as it enlarges, resulting in a bull’s-eye appearance. It may be warm but is not usually painful. Some patients develop additional EM lesions in other areas of the body after several days. Patients also experience symptoms of fatigue, chills, fever, headache, and muscle and joint aches, and swollen lymph nodes. In some cases, these may be the only symptoms of infection.
