Which patients should receive prophylaxis for lyme disease after a tick bite?

Those who meet the following criteria:

• tick attached > 36 hours (based on extent of engorgement with blood)
• local rate of infection of ticks with Borrelia burgdorferi exceeds 20% (see diagram below)
• prophylaxis can be started within 72 hours of tick removal

Prophylaxis regimen: doxycycline 200 mg in adults and 4 mg/kg (up to max of 200 mg)
in children > 8 y/o


Source

Jancin, B.  "Lyme Prophylaxis Risk Usually Outweighs Benefit"  ACEP News.  Oct 2010.