Tick Bite Prophylaxis

In areas that are highly endemic for Lyme disease, a single prophylactic dose of doxycycline (200 mg for adults or 4.4 mg/kg for children of any age weighing less than 45 kg) may be used to reduce the risk of acquiring Lyme disease after the bite of a high risk tick bite. Benefits of prophylaxis may outweigh risks when all of the following circumstances are present:

  1. Doxycycline is not contraindicated.
  2. The attached tick can be identified as an adult or nymphal I. scapularis tick.
  3. The estimated time of attachment is ≥36 h based on the degree of tick engorgement with blood or likely time of exposure to the tick.
  4. Prophylaxis can be started within 72 h of tick removal.
  5. Lyme disease is common in the county or state where the tick bite occurred (i.e., CT, DE, DC, MA, MD, ME, MN, NH, NJ, NY, PA, RI, VA, VT, WI, WV).

Antibiotic treatment following a tick bite is not recommended as a means to prevent anaplasmosis, babesiosis, ehrlichiosis, Rocky Mountain spotted fever, or other rickettsial diseases. There is no evidence this practice is effective, and it may simply delay onset of disease. Instead, persons who experience a tick bite should be alert for symptoms suggestive of tickborne illness and consult a physician if fever, rash, or other symptoms of concern develop.

Tularemia prophylaxis is recommended only in cases of laboratory exposure to infectious materials:

  • Doxycycline (100 mg orally BID X 14 days) is generally recommended for prophylaxis in adults.
  • Ciprofloxacin (500 mg orally BID) is not FDA-approved for prophylaxis of tularemia but has demonstrated efficacy in various studies, and may be an alternative for patients unable to take doxycycline.