Tick Bite



Even in high endemic areas for tick-borne diseases, the risk of infection with a tick-borne pathogen is very low. After a tick bite, patient concerns include:
  • Tick removal
  • Local effect of the bite
  • Possibility of acquiring a tick-borne illness:
    • Fear of contracting Lyme disease
    • Desire to be tested or treated for Lyme


  • Specific tick-borne infections are discussed in other chapters
  • Tick bite can be from different species of ticks of 2 major types:
    • Soft ticks (Ornithodoros):
      • Causes tick-borne relapsing fever
      • Only feed for minutes and therefore almost never provoke a visit to the ED
    • Hard ticks – especially Ixodes and Dermacentor:
      • Feed for several days to a week and therefore, more likely to be noticed by patient and lead to an ED visit
  • Lyme disease transmission:
    • Species of tick, stage of development, duration of attachment, and geography may all play a role in the possibility of developing Lyme disease
    • Most cases of Lyme are associated with bites from nymphal Ixodes scapularis ticks
    • Most cases of Lyme are transmitted only after the tick has been attached for 24–48 hr:
      • Degree of engorgement is a marker for duration of attachment

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