How does Lyme disease develop after a tick bite? - briefly
Transmission occurs when an infected tick remains attached for at least 24–48 hours, permitting Borrelia burgdorferi to enter the skin and multiply. The spirochete then disseminates via the bloodstream, causing early skin lesions and, if untreated, systemic involvement of joints, heart, and nervous system.
How does Lyme disease develop after a tick bite? - in detail
Lyme disease begins when an infected Ixodes tick attaches to the skin and feeds for at least 24 hours. During this period the tick’s salivary glands release the spirochete Borrelia burgdorferi into the dermal tissue. The bacteria rapidly multiply and spread locally, producing a characteristic erythema migrans lesion that expands over several days.
Within days to weeks, the spirochetes disseminate through the bloodstream and lymphatic system. This systemic phase involves:
- Migration to distant skin sites, generating additional erythema migrans lesions.
- Invasion of joints, where inflammatory responses cause arthralgia and swelling.
- Penetration of the central nervous system, leading to meningitis, cranial neuropathies, and radiculitis.
- Colonisation of cardiac tissue, potentially resulting in atrioventricular block and myocarditis.
The host immune response contributes to tissue damage. Early innate immunity attempts to contain the infection, while adaptive immunity produces specific antibodies that may not clear the pathogen entirely, allowing chronic manifestations in some patients.
Effective treatment requires prompt antibiotic therapy, typically doxycycline or amoxicillin, initiated during the early localized stage to prevent progression to disseminated disease. Delayed treatment increases the risk of persistent symptoms affecting joints, nerves, and the heart.