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  • Lyme disease is caused by Borrelia burgdorferi, a tickborne spirochete.

  • Clinical course can be prolonged and may involve multiple organ systems.

  • The most common cutaneous finding is the erythema migrans rash. Other cutaneous manifestations include lymphocytoma and acrodermatitis chronica atrophicans, which are only seen in European disease.

  • Diagnosis is typically made on clinical identification of the erythema migrans rash and/or serologic testing.

  • Early treatment with antibiotics (doxycycline, amoxicillin, or cefuroxime) is highly successful.


Lyme borreliosis, or Lyme disease, is the most commonly reported arthropod-borne illness in both the United States and Europe.1 The disease acquired its name from epidemiologic investigations in the 1970s of cases of oligoarticular arthritis among children in and around the town of Lyme, Connecticut.2 Certain features, including the tight clustering of cases in a heavily wooded area, and a rash that preceded arthritis that occurred predominantly in the summer, were suggestive that this was an arthropod-borne infectious disease.

In 1981, Burgdorfer isolated a new spirochetal bacterium, Borrelia burgdorferi, from the midgut of the Ixodes dammini tick (now Ixodes scapularis).3 Recovery of the organism from cutaneous lesions, cerebrospinal fluid, and blood specimens of patients with Lyme disease in both the United States4,5 and Europe6-8 definitively linked the disease with B. burgdorferi. Subsequently, additional genospecies causing Lyme disease were recognized. The original North American genospecies was designated B. burgdorferi sensu stricto and other species (including the 2 most prominent genospecies in other parts of the world, Borrelia garinii and ­Borrelia afzelii) were considered part of the B. ­burgdorferi sensu lato group. Recently, a change in the genus of Lyme disease causing Borrelia to Borreliella has been proposed to recognize significant differences with relapsing fever Borrelia. Borreliella encompasses all the genospecies that were originally designated as part of the sensu lato group. However, this has not been fully accepted so we will continue to use the Borrelia designation conventions.


Lyme disease occurs in the northern hemisphere in North America, Europe and Asia. The prevalence of strains differs between the continents, with B. burgdorferi being the predominant species in North America, B. garinii and B. afzelii being predominant in Asia, and all three present in Europe. Disease is often focal with high rates in some countries/states but not ­others. In Europe, the incidence is highest in the ­Austria, ­Belgium, Estonia, Lithuania, The ­Netherlands, Slovenia, and Sweden, with approximately 120,000 reported cases per year in Europe. The disease is less common in Asia, but has been reported in ­Russia, China, Korea, and Japan. In the United States, the majority of the cases are reported from the Northeast and mid-­Atlantic areas and the North Central part of the country. There is also a smaller foci of disease in the Northwestern United States.

Lyme disease Borrelia...

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