What is the preferred treatment for erythema migrans?

Preferred Treatment for Erythema Migrans

Doxycycline (100 mg twice per day for 10-14 days) is the preferred first-line treatment for erythema migrans in adults without specific contraindications. 1

First-Line Treatment Options

For Adults:

• Doxycycline: 100 mg twice daily for 10-14 days (10 days is sufficient for doxycycline) 1
• Amoxicillin: 500 mg three times daily for 14 days 1
• Cefuroxime axetil: 500 mg twice daily for 14 days 1

For Children:

• Amoxicillin: 50 mg/kg/day in 3 divided doses (maximum 500 mg per dose) for 14 days 1, 2
• Cefuroxime axetil: 30 mg/kg/day in 2 divided doses (maximum 500 mg per dose) for 14 days 1
• Doxycycline: For children ≥8 years old, 4 mg/kg/day in 2 divided doses (maximum 100 mg per dose) 1, 3

Treatment Selection Considerations

Doxycycline is preferred as first-line therapy for several reasons:

• Equivalent efficacy to other options with shorter treatment duration (10 days vs 14 days) 1
• Effective against Human Granulocytic Anaplasmosis (HGA), which may co-occur with Lyme disease 1
• Recent evidence supports even shorter courses (7 days) may be effective 4

However, doxycycline has important contraindications:

• Pregnancy and lactation: Avoid due to potential effects on fetal bone development 1, 3
• Children under 8 years: Contraindicated due to risk of permanent tooth discoloration 3
• Photosensitivity risk: Patients should avoid sun exposure during treatment 3

Second-Line Options

Macrolide antibiotics (azithromycin, clarithromycin, erythromycin) are not recommended as first-line therapy due to lower efficacy compared to the primary options 1, 5. They should be reserved for patients who:

• Have allergies or intolerances to all first-line agents 1
• Cannot take doxycycline, amoxicillin, or cefuroxime axetil for other medical reasons 1

When macrolides are used:

• Azithromycin: 500 mg daily for 7-10 days 1
• Clarithromycin: 500 mg twice daily for 14-21 days 1
• Erythromycin: 500 mg four times daily for 14-21 days 1

Patients treated with macrolides require closer monitoring to ensure resolution of symptoms 1.

Important Cautions

• First-generation cephalosporins (e.g., cephalexin) are ineffective for Lyme disease and should not be used 1
• When erythema migrans cannot be reliably distinguished from bacterial cellulitis, consider cefuroxime axetil or amoxicillin-clavulanate 1
• Jarisch-Herxheimer-like reactions may occur within the first 24 hours of treatment but are typically mild and transient 1
• Treatment failure is uncommon (<10%) but may require reassessment for possible CNS involvement 1

Duration of Therapy

Recent evidence supports shorter treatment courses:

• 10 days is sufficient for doxycycline 1, 6
• 14 days is recommended for amoxicillin and cefuroxime axetil due to their shorter half-lives 1
• A 2023 study demonstrated that 7 days of doxycycline was non-inferior to 14 days in European patients with solitary erythema migrans 4

Treatment Outcomes

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