The value of early treatment of deer tick bites for the prevention of Lyme disease.

OBJECTIVE

To determine if the early antibiotic treatment of deer tick bites prevented Lyme disease.

DESIGN

Prospective, double-blind, placebo-controlled, antibiotic treatment.

SETTING

Private practice in an area endemic for Lyme disease.

STUDY PARTICIPANTS

Patients between 3 and 19 years of age who received antibiotic treatment within 3 days following a deer tick bite.

INTERVENTIONS

Patients received an antibiotic or placebo and were followed up for stage I and II disease. All patients had blood drawn at the time of presentation and 6 weeks later for immunofluorescent antibodies (IFA).

MEASUREMENTS/MAIN RESULTS: One patient in the placebo group developed clinical Lyme disease associated with an IFA titer of 1:32, considered weakly positive. Three other patients in the placebo group developed an IFA titer of 1:32; one had an influenzalike illness and two had no symptoms. None of the study patients developed any neurologic, cardiac, or arthritic symptoms in the 1- to 3-year follow-up.

CONCLUSION

Based on the low frequency of illness, the absence of stage II disease, and the inability to establish the efficacy of early antibiotic treatment, we suggest that physicians not routinely use prophylactic antibiotics for deer tick bites.