Tick Bite

Basics

Description

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

Etiology

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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