What is Lyme disease that develops after a tick bite? - briefly
Lyme disease is a bacterial infection caused by Borrelia burgdorferi, transmitted to humans through the bite of infected Ixodes ticks. Early manifestations typically involve a distinctive expanding rash, fever, headache, and fatigue; untreated infection may progress to joint, cardiac, or neurological involvement.
What is Lyme disease that develops after a tick bite? - in detail
Lyme disease is a bacterial infection transmitted to humans through the bite of infected Ixodes ticks. The pathogen, Borrelia burgdorferi, colonizes the tick’s midgut and migrates to the salivary glands during feeding, entering the host’s skin within 24–48 hours of attachment.
Epidemiology
- Predominant in temperate regions of North America and Europe.
- Seasonal peak in late spring and early summer, coinciding with nymph activity.
- Risk increases with outdoor exposure in wooded or grassy habitats.
Pathogenesis
- After inoculation, spirochetes disseminate via the bloodstream and lymphatic system.
- Tissue tropism includes skin, joints, nervous system, and cardiac tissue, leading to diverse clinical presentations.
Clinical phases
Early localized (days to weeks)
- Erythema migrans: expanding red rash, often with central clearing.
- Flu‑like symptoms: fever, chills, headache, fatigue, myalgia.
Early disseminated (weeks to months)
- Multiple erythema migrans lesions.
- Neurological involvement: facial nerve palsy, meningitis, radiculitis.
- Cardiac manifestations: atrioventricular block, myocarditis.
Late (months to years)
- Arthritis: episodic swelling of large joints, especially the knee.
- Chronic neurologic problems: peripheral neuropathy, encephalopathy.
Diagnosis
- Clinical assessment of rash and exposure history.
- Serologic testing: two‑tier algorithm (ELISA followed by Western blot) after the first month of infection.
- Polymerase chain reaction (PCR) for synovial fluid or cerebrospinal fluid in specific cases.
Treatment
- Doxycycline (100 mg twice daily) for 14–21 days is first‑line for most presentations.
- Alternatives: amoxicillin or cefuroxime for patients with contraindications to doxycycline.
- Intravenous ceftriaxone recommended for severe neurologic or cardiac involvement.
Prevention
- Wear long sleeves and pants when entering tick‑infested areas.
- Apply EPA‑registered repellents containing DEET or picaridin.
- Perform thorough body checks after outdoor activities; remove attached ticks promptly with fine‑tipped tweezers, grasping close to the skin and pulling straight upward.
- Landscape management: keep grass short, remove leaf litter, create barrier zones between lawns and wooded edges.
Prompt recognition and appropriate antibiotic therapy markedly reduce the risk of long‑term complications.