How long does fever last after a tick bite? - briefly
Fever usually lasts three to seven days after a tick bite, extending up to two weeks if Lyme disease is present. Persistent fever beyond a week warrants medical assessment.
How long does fever last after a tick bite? - in detail
Fever following a tick bite usually begins within a few days to two weeks, depending on the pathogen transmitted. The most common agents and their typical fever courses are:
- Borrelia burgdorferi (Lyme disease). Early localized infection may cause a low‑grade fever lasting 3–7 days. If untreated, fever can persist intermittently for weeks while disseminated symptoms develop.
- Rickettsia rickettsii (Rocky Mountain spotted fever). Fever often appears 2–14 days after exposure and remains high (≥ 39 °C) for 5–10 days unless promptly treated with doxycycline, after which temperature usually normalizes within 48 hours.
- Anaplasma phagocytophilum (human granulocytic anaplasmosis). Fever starts 5–14 days post‑bite and typically lasts 7–10 days; antimicrobial therapy shortens this period to 2–3 days.
- Babesia microti (babesiosis). Fever may be continuous or intermittent for 1–2 weeks, sometimes extending longer in immunocompromised individuals.
Factors influencing fever duration include:
- Pathogen species and strain. Some strains produce more aggressive febrile responses.
- Host immune status. Immunosuppressed patients often experience prolonged or recurrent fever.
- Delay in diagnosis and treatment. Early administration of appropriate antibiotics generally reduces fever length by 50 % or more.
- Co‑infection with multiple tick‑borne organisms. Overlapping infections can extend febrile periods and complicate clinical picture.
When fever persists beyond the expected timeframe for the identified illness, or when it is accompanied by rash, severe headache, neck stiffness, respiratory distress, or organ dysfunction, immediate medical evaluation is required. Laboratory confirmation (PCR, serology, blood smear) guides targeted therapy, which in turn dictates the speed of fever resolution.