Which antibiotic is commonly used as first-line therapy for early localized Lyme disease presenting with erythema migrans?

• A. Doxycycline
• B. Amoxicillin
• C. Ceftriaxone
• D. Azithromycin

Answer: (A)

Doxycycline is the first-line choice for treating early localized Lyme disease when erythema migrans is present. It works well against Borrelia burgdorferi, is well absorbed when taken by mouth, and reaches tissues effectively, which makes it ideal for the localized stage of infection. The typical course is about two weeks (often 10–14 days, sometimes longer depending on guidelines). If doxycycline isn’t suitable—such as in pregnant patients or children under 8—amoxicillin is the preferred alternative. Ceftriaxone is reserved for more serious or disseminated disease, and azithromycin is not recommended due to lower efficacy and higher failure rates.