Lyme Disease Prophylaxis After Tick Bite

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 a high-risk tick bite.

Benefits of prophylaxis may outweigh risks when all of the following circumstances are present:

  1. Where the tick bite occurred, are ticks likely to be infected with Borrelia burgdorferi?
US map showing areas with high incidence of Lyme disease, and areas with local transmission
  1. Was the tick removed within the last 72 hours?
  1. Was the tick’s body engorged with blood (not flat)?


engorged tick


  1. Was the tick an Ixodes (blacklegged) tick?
nymph tick


black legged tick-flat


  1. Is doxycycline safe for the patient? Considerations include allergy to doxycycline, pregnancy, and lactation.

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. 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.


Nadelman RB, et al. Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite. N Engl J Med. 2001;345(2):79-84.

Harms MG, et al. A single dose of doxycycline after an Ixodes ricinus tick bite to prevent Lyme borreliosis: An open-label randomized controlled trial. J Infect. 2021;82(1):98-104.