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Last Updated: 6/23/2015  

Lyme Disease

  • Lyme disease is caused by B. burgdorferi, a spirochete transmitted by the bite of the tick species I. scapularis and I. pacificus. It is the most common tick-borne infection in North America and Europe.

  • Urge patients to avoid exposure to vector ticks in endemic areas and to promptly but carefully remove attached ticks.

  • Children in particular are likely to have unrecognized tick bites; inspect young patients carefully after potential exposure.

  • Be aware that pets may bring ticks into the house, even if the pet is itself protected against tick bites.

  • Do not routinely use antibiotics or serologic testing for the prevention of Lyme disease after a tick bite but consider one oral dose of doxycycline, 200 mg, if known tick bite in endemic area at least 36 hours from tick bite and within 72 hours from when the tick was removed.

  • Note the following three clinical stages of Lyme disease, with overlap symptoms and asymptomatic periods between the stages:

    • Acute localized (within one month of tick bite): erythema migrans, constitutional symptoms

    • Acute disseminated (weeks to months after tick bite): appearance of multiple erythema migrans-like lesions, constitutional symptoms, cardiac (heart block), neurological (peripheral and central disease such as seventh cranial nerve palsy and meningitis), transitory monoarticular or oligoarticular inflammatory arthritis

    • Chronic disseminated (months to years after tick bite): recurrent transitory or chronic inflammatory monoarthritis or oligoarthritis; rarely neurological (encephalomyelitis, peripheral neuropathy)

  • Use two-tiered serologic testing to confirm the diagnosis of Lyme disease in suspected cases of disseminated disease; serologic testing is not helpful in establishing the diagnosis in patients with a history of tick exposure in an endemic area presenting with erythema migrans.

  • Obtain an immunoblot only in patients with indeterminate or positive ELISA or IFA results.

  • The C6 peptide ELISA may be as specific as the Lyme disease immunoblot in confirming infection after an initial positive screening ELISA.

  • Be advised that there is no clear definition of post-Lyme disease syndrome beyond nonspecific symptoms and lab evidence of prior B. burgdorfei infection.

  • Treat erythema migrans with oral doxycycline or amoxicillin for 14 days.

  • Treat patients with radiculopathy or cranial nerve palsy with oral regimens. Children older than 8 years and adults with Lyme meningitis may be safely treated with oral doxycycline or with iv ceftriaxone. Patients with Lyme encephalitis should be treated with iv ceftriaxone.

  • Lyme carditis should be treated with iv ceftriaxone. Patients may be safely transitioned to oral therapy to complete the course of treatment once the cardiac abnormality has resolved.

  • Treat patients with Lyme arthritis with doxycycline or amoxicillin for 28 days.

  • Note that antibiotics have not been found effective in post-Lyme disease syndrome, although most patients experience gradually improvement over 6 to 12 months without treatment.

DOI: 10.7326/d091
The information included herein should never be used as a substitute for clinical judgment and does not represent an official position of ACP.
Author(s) and Disclosures:
Daniel W. Rahn, MD has nothing to disclose. Gary Wormser, MD has nothing to disclose. Nicholas Bennett, MBBChir, PhD has nothing to disclose. Justin Radolf, MD has nothing to disclose.

One or more of the present or past ACP Smart Medicine physician editors worked on this module and had nothing to disclose: Davoren Chick, MD, FACP; Deborah Korenstein, MD, FACP; Marjorie Lazoff, MD, FACP; Richard Lynn, MD, FACP.

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