Preferred Treatment for Erythema Migrans

First-Line Treatment Options

The Infectious Diseases Society of America recommends doxycycline (100 mg twice per day for 10-14 days) as the preferred first-line treatment for erythema migrans in adults without specific contraindications 1, 2
Amoxicillin (500 mg three times daily for 14 days) is a first-line treatment option for adults and children 1, 3
Cefuroxime axetil (500 mg twice daily for 14 days) is a first-line treatment option for adults and children 1, 4

Doxycycline is preferred as first-line therapy due to its equivalent efficacy to other options with shorter treatment duration (10 days vs 14 days) 1, 2
Doxycycline is effective against Human Granulocytic Anaplasmosis (HGA), which may co-occur with Lyme disease 1

Macrolide antibiotics (azithromycin, clarithromycin, erythromycin) are not recommended as first-line therapy due to lower efficacy compared to the primary options 1, 5
Azithromycin (500 mg daily for 7-10 days) is a second-line treatment option for patients who cannot take first-line agents 3
Clarithromycin (500 mg twice daily for 14-21 days) and erythromycin (500 mg four times daily for 14-21 days) are second-line treatment options for patients who cannot take first-line agents 3

First-generation cephalosporins (e.g., cephalexin) are ineffective for Lyme disease and should not be used 1
Jarisch-Herxheimer-like reactions may occur within the first 24 hours of treatment but are typically mild and transient 6
Treatment failure is uncommon (<10%) but may require reassessment for possible CNS involvement 7

10 days is sufficient for doxycycline 2
14 days is recommended for amoxicillin and cefuroxime axetil due to their shorter half-lives 1

Most patients respond promptly and completely to appropriate antibiotic therapy 7
The primary goal is to prevent progression to late manifestations of Lyme disease, which is achieved with appropriate early treatment 1, 6

The Infectious Diseases Society of America recommends alternative first-line oral regimens, including amoxicillin 500 mg orally three times daily for 14 days, particularly for children under 8 years of age and pregnant women, who should avoid doxycycline 8

Before initiating oral therapy, carefully assess for subtle neurologic symptoms, as patients with subtle distal paresthesias or memory impairment at study entry may develop neuroborreliosis, and consider intravenous therapy with ceftriaxone 2 g daily instead 8, 9, 10

Consider co-infection with Babesia microti or Anaplasma phagocytophilum if the patient presents with high-grade fever persisting >48 hours despite appropriate Lyme treatment, unexplained leukopenia, thrombocytopenia, or anemia, or more severe initial symptoms than typically seen with Lyme disease alone 8, 11
Doxycycline provides coverage for HGA but not babesiosis 11