Lyme disease is an infectious disease transmitted to humans through the bite of infected ticks.
Erythema migrans develops at the site of tick bite usually within 1 to 2 weeks and is a pathognomic feature.
Constitutional symptoms such as fever, headache, myalgias, fatigue, and arthralgias may occur.
Complications of Lyme disease may be neurological, cardiac, or musculoskeletal.
Mainstay of treatment is antibiotic therapy.
There is currently no vaccine; prevention is centred around reducing exposure to ticks.
Lyme disease is a zoonotic infection caused by a spirochete of genus Borrelia, which is transmitted to humans by ticks. Zoonotic diseases are transmitted between vertebrate animals and humans. Animals serve as the primary reservoir of Borrelia. Ticks become infected by feeding on an infected animal. The most common initial manifestation is a typical skin lesion known as erythema migrans. Later manifestations may include arthritis, or central nervous system or cardiac involvement.
History and exam
Key diagnostic factors
- presence of risk factors
- erythema migrans
- constitutional symptoms
Other diagnostic factors
- facial palsy
- arthritis or arthralgia
- regional lymphadenopathy
- stiff neck
- lymphocytoma cutis
- acrodermatitis chronica atrophicans
- atrioventricular (AV) block or myopericarditis
- encephalomyelitis, peripheral neuropathy, encephalopathy
- exposure to infected ticks
- outdoor activities
- tick bite duration
1st investigations to order
- enzyme immunoassay or immunofluorescence assay
Investigations to consider
- Lyme-specific IgM and IgG (immunoblot assays)
- skin biopsy culture
- polymerase chain reaction (PCR)
known tick bite
recurrent or persistent arthritis
- Tickbite allergy
- Erythema multiforme
- 2020 guidelines for the prevention, diagnosis and treatment of Lyme disease
- Lyme disease
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