Management of tick bites and lyme disease during pregnancy

Lyme disease results from the bite of a black-legged tick, populations of which have now become established in parts of Nova Scotia, southeastern Quebec, southern Ontario from the Thousand Islands through the geographic regions on the north shore of Lake Ontario and Lake Erie, southeastern Manitoba, and British Columbia's Lower Mainland, Fraser Valley, and Vancouver Island. It takes more than 24 hours of attachment to transfer the spirochete Borrelia burgdorferi to the bitten animal or human. The diagnosis of Lyme disease is primarily clinical, with early Lyme disease characterized by a skin lesion (erythema migrans, a bull's-eye rash), which expands out from the site of the tick bite, and is often accompanied by influenza-like symptoms, arthralgia, myalgia, and fever. These signs and symptoms can present anywhere from three to 30 days after the tick bite. The management of pregnant women with a tick bite or suspected Lyme disease should be similar to that of non-pregnant adults, except that doxycyline, the first line antibiotic of choice, should not be used in pregnant women because of risk of permanent tooth discolouration and possible impact on bone formation in the fetus. An algorithm for the management of tick bites in pregnancy is presented. Clinical, serological, and epidemiological studies have all failed to demonstrate a causal association between infection with B. burgdorferi and any adverse pregnancy outcomes regardless of whether maternal exposure occurs before conception or during pregnancy itself.