Duration of Antibiotic Treatment for Early Lyme Disease

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The study is titled "Duration of Antibiotic Therapy for Early Lyme Disease. A Randomized, Double-Blind, Placebo- Controlled Trial." It is in the 6 May 2003 issue of Annals of Internal Medicine (volume 138, pages 697-704). The authors are G.P. Wormser, R. Ramanathan, J. Nowakowski, D. McKenna, D. Holmgren, P. Visintainer, R. Dornbush, B. Singh, and R.B. Nadelman.

What is the problem and what is known about it so far?

Lyme disease is a bacterial infection transmitted to humans by ticks. People who hike, camp, work, or live in or near wooded areas during summer months are most at risk for Lyme disease. People bitten by an infected tick may develop a large area (diameter >2 in) of redness (rash) around the bite days to weeks later. As this rash gradually expands, a bright red outer border and a central pale area of clearing are often seen (the rash may also be uniformly red). This type of rash is called erythema migrans. Symptoms such as chills, fever, fatigue, headache, and joint pains may accompany the rash or may develop days after the rash appears. If the infection is not treated, symptoms may persist for several weeks. Also, complications involving the heart, joints, or nervous system may develop, sometimes as long as 1 to 2 years later. Doctors often give patients with erythema migrans and early, uncomplicated Lyme disease antibiotics for 3 to 4 weeks. It is not clear whether such lengthy treatment is needed.

Why did the researchers do this particular study?

To compare three regimens for treating early Lyme disease.

Who was studied?

180 adults with erythema migrans and early Lyme disease seen at a university medical center in New York.

How was the study done?

Patients were randomly assigned to one of three groups. The first group received a single dose of an antibiotic (ceftriaxone) in their vein followed by 10 days of antibiotic pills (doxycycline twice daily) and then by 10 days of dummy pills (placebo twice daily). The second group received placebo fluid (sugar water) in their vein followed by 10 days of doxycycline pills and then by 10 days of placebo pills. The third group received placebo fluid in their vein followed by 20 days of doxycycline pills. Neither the patients nor their doctors were told who got which treatment. The researchers followed patients closely for 30 months to see whether the rash and symptoms went away (complete response). They considered treatment to have failed if the rash and symptoms persisted; if the rash or symptoms initially went away but came back; or if long-term heart, joint, or nervous system complications occurred. The researchers compared outcomes among the three groups.

What did the researchers find?

Outcomes for the three groups were similar. After 20 days, about two thirds of the patients in each group had complete responses. After 30 months, about 85% to 90% of the patients in each group had complete responses. Therapy failed in one patient in the second group who had infection of the nervous system (meningitis) that improved with 2 weeks of ceftriaxone treatment. Patients in the first group more often had treatment side effects (mostly diarrhea) than patients in the other two groups.

What were the limitations of the study?

This study applies only to people with early Lyme disease associated with erythema migrans. It may not apply to patients with Lyme disease involving sites other than skin (for example, the nervous system or the joints).

What are the implications of the study?

Doxycycline alone for 10 days is sufficient treatment for patients with erythema migrans and early, uncomplicated Lyme disease.