- "Lyme disease is a zoonotic, multisystem illness caused by the
spirochete B. burgdorferi, which is transmitted by certain Ixodes spp
- Approximately 30,000 cases are reported to the CDC each year,
primarily from high-incidence states located in the northeast
(Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire,
New Jersey, New York, Pennsylvania, Rhode Island, and Vermont) and
north central (Minnesota and Wisconsin) United States.
- Acute clinical illness is usually characterized by fever and
constitutional symptoms combined with a distinctive rash, erythema
migrans (EM), which develops at the site of the tick bite in
approximately 70 to 80 percent of patients.4 However, without early
appropriate antibiotic therapy, infection can disseminate to other
tissues, causing peripheral and central neuropathy, arthritis, and
When to Provide Prophylaxis
- "For prevention of Lyme disease after a recognized tick bite,
routine use of antimicrobial prophylaxis or serologic testing is not
recommended. A single dose of doxycycline may be offered to adult
patients (200 mg) and to children ≥8 years of age (4 mg/kg, up to a
maximum dose of 200 mg) when all of the following circumstances exist:
- The attached tick can be reliably identified as an adult or
nymphal I. scapularis tick that is estimated to have been attached for
≥36 hours on the basis of the degree of engorgement of the tick with
blood or on certainty about the time of exposure to the tick.
- Prophylaxis can be started within 72 hours of the time that the tick was removed.
- Ecologic information indicates that the local rate of infection of these ticks with B. burgdorferi is ≥20 percent.
- Doxycycline is not contraindicated."
Source: Clin Infect Dis. 2006;43:1089-1134.