Lyme disease

Last updated: March 14, 2023

Summarytoggle arrow icon

Lyme disease (or borreliosis) is a tick-borne infection caused by certain species of the Borrelia genus (B. burgdorferi in the US, predominantly B. afzelii and B. garinii in Asia and Europe). There are three stages of Lyme disease. Stage I (early localized disease) is characterized by erythema migrans (EM), an expanding circular red rash at the site of the tick bite, and may be associated with flu‑like symptoms. In stage II (early disseminated disease), patients may present with neurological symptoms (e.g., facial palsy), migratory arthralgia, and cardiac manifestations (e.g., myocarditis). Stage III (late disease) is characterized by chronic arthritis and CNS involvement (late neuroborreliosis) with possible progressive encephalomyelitis. In Asia and Europe, further skin manifestations may also occur in stage II (lymphadenitis cutis benigna) and stage III (acrodermatitis chronica atrophicans). Lyme disease is a clinical diagnosis in patients presenting with EM. Serological tests (e.g., Western blot; enzyme-linked immunosorbent assay) can help support the clinical diagnosis, especially if the presence of EM is not known or questionable. Lyme disease is treated with antibiotics; the drugs of choice are doxycycline for localized disease and ceftriaxone for disseminated disease.

Epidemiologytoggle arrow icon

  • Incidence: most commonly reported vector-borne disease in the US
  • Geographical distribution: primarily the Northeast and upper Midwest of the US


Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

  • Pathogen
  • Vector
    • Various tick species: mainly Ixodes scapularis (deer or black-legged tick) in the northeastern and upper midwestern US
      • Ixodes pacificus (western black-legged tick) in the northwestern US
      • Ixodes ricinus (castor bean tick) in Europe
    • Typically found in forests or fields on tall brush or grass
    • The incidence of Lyme disease is highest between April and October (especially from June to August).
    • Increased risk of disease for:
      • Outdoor workers (landscapers, farmers, etc.)
      • Outdoor enthusiasts (i.e., hikers, hunters, etc.)
  • Reservoir hosts
    • Deer, cattle
    • Peromyscus leucopus, the white‑footed mouse, is the primary reservoir of B. burgdorferi in the US.


Clinical featurestoggle arrow icon

Stage I (early localized Lyme disease) [2][3][4]

Symptoms develop within 7–14 days after a tick bite

Stage II (early disseminated Lyme disease) [2][3][4]

Symptoms develop 3–10 weeks after a tick bite

Stage III (late Lyme disease) [2][3][4]

Symptoms develop months to years after the initial infection

  • Lyme arthritis [7]
    • Inflammation of joint tissue colonized by Borrelia bacteria that may be intermittent or chronic and may cause permanent damage if left untreated
    • Intermittent or persistent
    • Monoarthritis or asymmetric oligoarthritis that typically affects the large joints (especially knee or elbow)
  • Late neuroborreliosis manifestations include:
  • Acrodermatitis chronica atrophicans (Herxheimer disease)
    • Chronic progressive dermatological disease due to infection with Borrelia afzelii that occurs only in Europe and Asia and most commonly affects women > 40 years of age
    • Typically involving the extensor surface of the extremities

To remember important symptoms of Lyme disease, think of someone making a FACE (Facial nerve palsy, Arthritis, Carditis, Erythema migrans) when biting into a lime.

Diagnosticstoggle arrow icon


Two‑step serological testing

Other tests

Borrelia-specific intrathecal antibodies with normal protein and without pleocytosis indicate a past infection. Detection of elevated antibodies alone does not provide conclusive evidence of an active infection


Differential diagnosestoggle arrow icon


The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Stages Presentation General therapy Therapy in pregnant/nursing patients
Localized Lyme disease
Disseminated Lyme disease

Doxycycline is relatively contraindicated in pregnant/nursing women due to its adverse effects on growing bones and teeth. Administer amoxicillin (or cefuroxime axetil) instead.

If infection is likely (e.g., EM is present), start antibiotic treatment.

Possible complications following successful antibiotic treatment

  • Post-Lyme disease syndrome (PLDS)
    • Description: a somewhat controversial syndrome (the medical community does not agree on its existence) following successful treatment of Lyme disease that is associated with pain, fatigue, and difficulty concentrating that lasts > 6 months [14]
    • Differential diagnosis: somatoform disorders, unsuccessfully treated chronic Lyme disease
    • Treatment: symptomatic treatment with general medical and psychosomatic support


Preventiontoggle arrow icon

  • There is no approved vaccine on the market for Lyme disease. There was a Lyme disease vaccine in the past that offered temporary protection, but it was discontinued in 2002 because of low demand.
  • Avoid prime habitats in areas known for Lyme disease.
  • Tick bite prevention: Prevent and properly manage tick bites to avoid exposure.
    • Wear protective clothing: e.g., long-sleeved shirts, long pants, and light colors.
    • Use tick repellent and pesticides.
    • Check body for tick bites.
    • Remove ticks immediately
      1. Grasp the tick with tweezers directly above the skin's surface.
      2. Carefully pull upward with even pressure.
      3. Do not use nail polish remover, adhesives, oils, or similar substances to remove the tick. The tick should be removed quickly rather than waiting for it to detach slowly.
      4. Disinfect the site of the bite and dispose of the tick
    • Observe the bite site for early detection of EM.

Post‑exposure prophylaxis for Lyme disease [16]

  • Although controversial, post-exposure prophylaxis may be considered for patients who meet all of the following criteria:
    • The attached tick can be identified as an adult or nymphal Ixodes scapularis tick.
    • The tick has been attached for ≥ 36 hours (based on degree of engorgement or amount of time since exposure).
    • Prophylaxis can be started within 72 hours of tick removal.
    • The local rate of tick infection with B. burgdorferi is ≥ 20% (known to occur in parts of New England, parts of the mid‑Atlantic states, and parts of Minnesota and Wisconsin).
    • The patient can take doxycycline (e.g., the person is neither pregnant nor breastfeeding, nor a child < 8 years of age).
  • If the patient meets all the above criteria, 200 mg of doxycycline can be given to adults and 4.4 mg/kg to children of any age weighing < 45kg (maximum dose: 200 mg). [13]

Referencestoggle arrow icon

  1. Lyme Disease - Data and Statistics. Updated: December 19, 2016. Accessed: February 8, 2017.
  2. Kasper DL, Fauci AS, Hauser SL, Longo DL, Lameson JL, Loscalzo J. Harrison's Principles of Internal Medicine. McGraw-Hill Education ; 2015
  3. Miller JB, Aucott JN. Stages of Lyme Arthritis. J Clin Rheumatol. 2021; 27 (8): p.e540-e546.doi: 10.1097/rhu.0000000000001513 . | Open in Read by QxMD
  4. Steere AC, Strle F, Wormser GP, et al. Lyme borreliosis. Nature Reviews Disease Primers. 2016; 2 (1).doi: 10.1038/nrdp.2016.90 . | Open in Read by QxMD
  5. Lyme disease - Signs and symptoms. . Accessed: April 27, 2020.
  6. Marx JA, Hockberger RS, Walls RM et al. Rosen's Emergency Medicine - Concepts and Clinical Practice. Saunders ; 2013
  7. Arvikar SL, Steere AC. Diagnosis and Treatment of Lyme Arthritis. Infect Dis Clin North Am. 2015; 29 (2): p.269-280.doi: 10.1016/j.idc.2015.02.004 . | Open in Read by QxMD
  8. Eckman EA, Clausen DM, Herdt AR, Pacheco-Quinto J, Halperin JJ. Specificity and Diagnostic Utility of Cerebrospinal Fluid CXCL13 in Lyme Neuroborreliosis. Clinical Infectious Diseases. 2020.doi: 10.1093/cid/ciaa335 . | Open in Read by QxMD
  9. Meyerhoff JO. Lyme Disease. In: Diamond HS, Lyme Disease. New York, NY: WebMD. Updated: March 14, 2016. Accessed: February 7, 2017.
  10. Hu L. Diagnosis of Lyme disease. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Last updated: January 11, 2017. Accessed: February 8, 2017.
  11. Horowitz DL, Katzap E, Horowitz S, Barilla-LaBarca ML. Approach to Septic Arthritis. Am Fam Physician. 2011; 84 (6): p.653-660.
  12. Binder AM, Armstrong PA. Patient characteristics, treatment patterns, and outcomes of Rickettsial diseases among a commercially insured population in the United States, 2005–2017. Scientific Reports. 2021; 11 (1).doi: 10.1038/s41598-021-96463-9 . | Open in Read by QxMD
  13. Lyme disease - Lyme disase vaccine. Updated: November 17, 2015. Accessed: February 8, 2017.
  14. Controversies & Challenges in Treating Lyme and Other Tick-borne Diseases.,than%20six%20months%20following%20antibiotic.&text=ILADS%20agrees%20that%20for%20many,individuals%2C%20the%20infection%20is%20chronic.. . Accessed: September 10, 2020.
  15. Wormser GP, Dattwyler RJ, Shapiro ED et al. The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2006; 43 (9): p.1089-1134.doi: 10.1086/50866710.1086/508667 . | Open in Read by QxMD
  16. Wormser GP, Dattwyler RJ, Shapiro ED, et al. The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America. Clinical Infectious Diseases. 2006; 43 (9): p.1089-1134.doi: 10.1086/508667 . | Open in Read by QxMD

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