(Lyme Borreliosis, Borrelia burgdorferi Infection)

Clinical Manifestations of Lyme disease are divided into 3 stages: early localized, early disseminated, and late disease. Early localized disease is characterized by a distinctive rash, erythema migrans , at the site of a recent tick bite. Erythema migrans is the most common manifestation of Lyme disease in children; only a small proportion of children are diagnosed with early disseminated or late Lyme disease without a history of erythema migrans. Erythema migrans begins as a red macule or papule that usually expands over days to weeks to form a large, annular, erythematous lesion that typically increases in size to 5 cm or more in diameter, sometimes with partial central clearing. The lesion usually is painless and not pruritic. Localized erythema migrans can vary greatly in size and shape and may have vesicular or necrotic areas in its center and can be confused with cellulitis. Fever, malaise, headache, mild neck stiffness, myalgia, and arthralgia often accompany the rash of early localized disease.

Approximately 15% of patients with Lyme disease come to medical attention with early disseminated disease, most commonly multiple erythema migrans. This rash usually occurs several weeks after an infective tick bite and consists of secondary annular, erythematous lesions similar to, but usually smaller than, the primary lesion. These lesions reflect spirochetemia with cutaneous dissemination. Other common manifestations of early disseminated illness (that may occur with or without rash) are palsies of the cranial nerves (especially cranial nerve VII), lymphocytic meningitis, and conjunctivitis. Systemic symptoms, such as arthralgia, myalgia, headache, and fatigue, also are common during the early disseminated stage. Carditis, which usually manifests as various degrees of heart block, occurs rarely in children. Occasionally, people with early Lyme disease have concurrent human granulocytic anaplasmosis or babesiosis, transmitted by the same tick, which may contribute to symptomatology.

Late disease is characterized most commonly by relapsing arthritis that usually is pauciarticular and affects large joints, particularly knees. Arthritis can occur without a history of earlier stages of illness (including erythema migrans). Peripheral neuropathy and central nervous system manifestations also can occur rarely during late disease. Children who are treated with antimicrobial agents in the early stage of disease almost never develop late disease.

Because congenital infection occurs with other spirochetal infections, there has been concern that an infected pregnant woman could transmit Borrelia burgdorferi to her fetus. No causal relationship between maternal Lyme disease and abnormalities of pregnancy or congenital disease caused by B burgdorferi has been documented conclusively. No evidence exists that Lyme disease can be transmitted via human milk.