Lyme Disease (Adults & Paediatrics)

Lyme Disease (Adults & Paediatrics)


Tick-borne disease; vector = Ixodes scapularis (aka deer tick or blacklegged tick)

Tick Identification

  • Usually within 7-14 days (range 3-30 days) after tick bite
  • Erythema migrans (EM) rash > 5 cm with central clearing, "bull's eye"
  • Homogenous ovoid rash > 5 cm without central clearing
  • May reach a diameter of 20+ cm
  • May have non-specific signs & symptoms resembling a viral syndrome
  • Weeks to months after tick bite
  • Multiple EM lesions (sign of spirochetemia)
  • Neurologic: lymphocytic meningitis, unilateral/bilateral cranial nerve palsies (esp facial nerve), radiculopathy, peripheral neuropathy, and rarely cerebellar ataxia & encephalomyelitis
  • Carditis: AV heart block, sometimes mild pericarditis
  • Ocular: many sites, most commonly conjunctivitis
  • Months to years after tick bite
  • Intermittent or persistent arthritis: monoarticular or oligoarticular (large joints, esp the knee)
  • Acrodermatitis chronica atrophicans (in Europe)
  • Neurologic: peripheral neuropathy, encephalomyelitis
  • Lyme disease acquired in Europe can present with more neurologic forward symptoms
  • Caused by Borrelia afzelii & Borrelia garinii


Additional Information

  • Lantos PM, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis, and Treatment of Lyme Disease. Arthritis Rheumatol. 2021 Jan;73(1):12-20. doi: 10.1002/art.41562. Epub 2020 Nov 29. PMID: 33251716.
  • Health Quality Ontario. Management of Tick Bites and Investigation of Early Localized Lyme Disease. 2018. Available online
  • Hu L, Shapiro ED. (2021 May) Treatment of Lyme Disease. In Hall, KK (ed). UpToDate. Retrieved June, 2022.
  • Centers for Disease Control and Prevention. (2022 Jan) Lyme Disease. Retrieved June 2022 from

Approved June 2022