Symptoms can be divided into early and late stages, but any of the findings can occur any time, alone or with other symptoms. The initial manifestation is a skin lesion, erythema chronicum migrans, which originates at the site of the tick bite and spreads in an expanding circle, often with central clearing. The lesion is accompanied by such constitutional symptoms as malaise, fatigue, arthralgia, headache, and stiff neck. From this early stage, the disease may progress to a second stage in which symptoms and signs of meningitis, neuritis, or cardiac occur weeks to months after the tick bite, and are characterized by chronic neurologic symptoms and most commonly by pauciarticular arthritis. Infection during pregnancy can cause infection of the fetus, and can causing some birth defects, but no pattern has thus far been established.
Early treatment is advised after diagnosis.
Serologic findings may be negative in the early stage of Lyme disease but become positive as the disease progresses. Incomplete clinical presentations are common, so Lyme disease should be considered in all children with pauciarticular arthritis who have been in an area in which the tick is endemic. A significant elevation in antibody titers is a prerequisite to a definitive diagnosis of Lyme disease. Length and route of treatment is decided based on the patient's condition. An oral antibiotic such as penicillin, ampicillin, erythromycin or tetracycline is usually the preferred treatment.