How should Lyme disease caused by a tick bite be treated? - briefly
The standard approach is a 2‑ to 4‑week oral course of doxycycline, with amoxicillin or cefuroxime as alternatives for those unable to take doxycycline; intravenous ceftriaxone is reserved for neurologic or cardiac manifestations.
How should Lyme disease caused by a tick bite be treated? - in detail
Lyme disease transmitted by ticks requires prompt antimicrobial therapy after confirmation of infection. Diagnosis is based on a characteristic erythema migrans rash, exposure history, and, when needed, serologic testing for IgM and IgG antibodies. Treatment decisions depend on disease stage and patient characteristics.
For early localized infection (≤ 30 days, single erythema migrans), oral doxycycline 100 mg twice daily for 10–14 days is first‑line. Alternatives include amoxicillin 500 mg three times daily or cefuroxime axetil 500 mg twice daily for the same duration, used when doxycycline is contraindicated.
Early disseminated disease (multiple skin lesions, neurologic involvement, cardiac manifestations) also responds to oral doxycycline for 14–21 days. If meningitis or severe neurologic involvement occurs, intravenous ceftriaxone 2 g daily for 14–28 days is recommended. Intravenous cefotaxime is an acceptable substitute.
Late disseminated disease (arthritis, chronic neurologic symptoms) is treated with oral doxycycline 100 mg twice daily for 28 days, or amoxicillin/cefuroxime for the same period. Persistent arthritis may require intra‑articular corticosteroid injection after completing antibiotics; systemic steroids are not advised.
Special populations require dosage adjustments. Children younger than 8 years receive amoxicillin or cefuroxime; doxycycline is reserved for those ≥ 8 years. Pregnant or lactating women are treated with oral amoxicillin 500 mg three times daily for 28 days; ceftriaxone is used intravenously for neurologic disease. Patients with severe β‑lactam allergy receive macrolides (e.g., azithromycin 500 mg daily) though efficacy is lower.
Supportive care includes analgesics for joint pain and antipyretics for fever. Anti‑inflammatory drugs alleviate arthritic discomfort; steroids have no proven benefit and may delay bacterial clearance. Physical therapy helps restore joint function after arthritis resolves.
Follow‑up evaluation occurs 2–4 weeks after therapy completion. Clinical improvement should be evident; persistent or worsening symptoms warrant repeat serology, imaging, or cerebrospinal fluid analysis. Retreatment with a different antibiotic class is indicated for documented treatment failure.