Erythema migrans rashes occur in 70-80 percent of infected patients, with onset between 3-30 days (average of 7 days) after being bitten by a tick carrying Borrelia burgdorferi, or less commonly, Borrelia mayonii. The erythema migrans rash of early localized Lyme disease occurs at the site of the tick bite. If not treated, the bacteria can spread and can cause multiple erythema migrans rashes at other places on the body. While sometimes warm to the touch, rashes are usually not painful or itchy. While a bull’s-eye pattern is considered the “classic” presentation, erythema migrans can present in a variety of ways.
