What is a Lyme tick bite? - briefly
A bite from an infected black‑legged tick (Ixodes species) transmits the bacterium Borrelia burgdorferi, the pathogen responsible for Lyme disease. It often produces an expanding erythema‑migrans rash and flu‑like symptoms within days to weeks after attachment.
What is a Lyme tick bite? - in detail
A bite from the black‑legged tick (Ixodes scapularis or Ixodes pacificus) introduces the bacterium Borrelia burgdorferi, the agent of Lyme disease, into the skin. Transmission generally requires the tick to remain attached for at least 24–48 hours; the longer the attachment, the higher the probability of infection.
The bite site often appears as a small, red papule that may expand into a characteristic expanding rash with a clear central area, commonly called a “target” or “bull’s‑eye” lesion. This rash typically emerges 3–30 days after the tick is removed.
Early manifestations include:
- Expanding erythema at the attachment point
- Flu‑like symptoms: fever, chills, headache, fatigue, muscle and joint aches
- Neck stiffness or facial nerve palsy in some cases
If untreated, the infection can spread to multiple organ systems, leading to:
- Multiple skin lesions
- Cardiac involvement (e.g., atrioventricular block)
- Neurological signs (e.g., meningitis, radiculopathy)
- Joint inflammation, especially in large joints such as the knee
Diagnosis relies on clinical assessment of the rash and symptom pattern, supported by serologic testing for antibodies against B. burgdorferi when the presentation is atypical or prolonged. Laboratory confirmation is most reliable after the second week of illness, when antibody levels rise.
Standard therapy consists of oral doxycycline for 10–21 days in most adults and children over eight years old. Alternative agents include amoxicillin or cefuroxime for patients with contraindications to doxycycline. Intravenous ceftriaxone is reserved for severe neurological or cardiac involvement. Prompt treatment prevents progression to late‑stage disease and reduces the risk of long‑term complications.