What should be injected after a tick bite? - briefly
A single dose of doxycycline (200 mg) taken within 72 hours of the bite is the recommended prophylactic injection. If doxycycline cannot be used, a macrolide antibiotic such as azithromycin may be considered.
What should be injected after a tick bite? - in detail
A prompt injection is recommended when a tick bite poses a risk of Lyme disease or other tick‑borne infections. The first‑line prophylactic agent is a single dose of doxycycline, 200 mg for adults and 4 mg/kg (maximum 200 mg) for children ≥ 8 years, taken within 72 hours of removal. This regimen reduces the incidence of early Lyme disease when the attached tick has been feeding for ≥ 36 hours and the local infection rate exceeds 20 %.
If doxycycline is contraindicated—due to allergy, pregnancy, or age < 8 years—alternatives include a 5‑day course of amoxicillin (500 mg three times daily for adults) or cefuroxime axetil (500 mg twice daily). Initiation should occur as soon as possible after the bite, but not later than 72 hours.
For bites occurring in regions where tick‑borne rickettsial diseases are endemic, a single dose of azithromycin (1 g) may be considered, especially when doxycycline cannot be used. In areas with a high prevalence of tick‑borne encephalitis, a single dose of the inactivated TBE vaccine is advised for unvaccinated individuals, administered promptly after exposure.
When the bite is associated with potential rabies exposure—such as a bite from a bat or a tick that has fed on a rabid animal—a rabies post‑exposure prophylaxis regimen is indicated: one dose of human rabies immune globulin infiltrated around the wound, followed by the standard four‑dose vaccine series on days 0, 3, 7, and 14.
Monitoring for signs of infection (fever, erythema, expanding rash) should continue for at least 30 days. If symptoms develop, immediate medical evaluation and targeted therapy based on laboratory confirmation are required.