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 neurologic, cardiac, or musculoskeletal.
Mainstay of treatment is antibiotic therapy.
There is currently no vaccine; prevention is centered 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
- 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
Janak Koirala, MD, MPH, FACP, FIDSA
Professor of Medicine and Infectious Diseases
Division of Infectious Diseases
Southern Illinois University School of Medicine
JK declares that he has no competing interests.
Dr Janak Koirala would like to gratefully acknowledge Dr Tin Han Htwe and Dr Cristian A. Spiel, previous contributors to this topic.
THH and CAS declare that they have no competing interests.
Raymond J. Dattwyler, MD
Professor of Medicine and Microbiology/Immunology
Chief of Allergy, Immunology and Rheumatology
New York Medical College
RJD declares that he has no competing interests.
Ionita Catalina, MD
Assistant Professor of Neurology and Neurosurgery
SUNY at Buffalo
Millard Fillmore Gates Hospital - Kaleida Stroke Center
IC declares that she has no competing interests.
Graham Fry, MB, FRCSI, DTM&H
Lecturer in Tropical Medicine
University College Dublin
Tropical Medical Bureau
GF declares that he has no competing interests.
Andras Lakos, MD, PhD
Centre for Tick-Borne Diseases
AL is an author of a reference cited in this topic.
- Tickbite allergy
- Erythema multiforme
- 2020 guidelines for the prevention, diagnosis and treatment of Lyme disease
- Lyme disease
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