American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended treatment for Lyme disease with a single erythema migrans lesion?

1. Intravenous penicillin G

2. Oral doxycycline

3. Oral azithromycin

4. Intravenous ceftriaxone

The correct answer is: Oral doxycycline

The recommended treatment for Lyme disease with a single erythema migrans lesion is oral doxycycline. Doxycycline is a tetracycline antibiotic that is effective against Borrelia burgdorferi, the bacterium that causes Lyme disease. This approach is particularly indicated in cases with a single erythema migrans because it provides a high cure rate with a straightforward oral administration route. Doxycycline is also preferred in certain patient populations, including adults and children over eight years of age, due to its effectiveness and the favorable side effect profile compared to intravenous treatments. Oral therapy can typically lead to an improvement in symptoms within a few days, making doxycycline a convenient and effective first-line option for early localized Lyme disease. Other treatments, such as intravenous penicillin G or ceftriaxone, are generally reserved for more severe cases or neurological manifestations of Lyme disease, as they involve a more aggressive treatment approach and the need for hospitalization. Oral azithromycin is not recommended for Lyme disease treatment, as it has not shown sufficient efficacy against the infection compared to doxycycline.