Lyme disease

Last reviewed: 29 Aug 2023

Last updated: 06 May 2021

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.

Definition

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

More key diagnostic factors

Other diagnostic factors

facial palsy
arthritis or arthralgia
regional lymphadenopathy
stiff neck
lymphocytoma cutis
acrodermatitis chronica atrophicans
atrioventricular (AV) block or myopericarditis
radiculoneuropathy
encephalomyelitis, peripheral neuropathy, encephalopathy

Other diagnostic factors

Risk factors

exposure to infected ticks
outdoor activities
tick bite duration

More risk factors

Diagnostic investigations

1st investigations to order

enzyme immunoassay or immunofluorescence assay

More 1st investigations to order

Investigations to consider

Lyme-specific IgM and IgG (immunoblot assays)
skin biopsy culture
polymerase chain reaction (PCR)
ECG

More investigations to consider

Treatment algorithm

INITIAL

known tick bite

ACUTE

erythema migrans

cardiac involvement

neurologic disease

arthritis

ONGOING

recurrent or persistent arthritis

Contributors

Authors

Janak Koirala, MD, MPH, FACP, FIDSA

Professor of Medicine and Infectious Diseases

Division of Infectious Diseases

Southern Illinois University School of Medicine

Springfield

Disclosures

JK declares that he has no competing interests.

Acknowledgements

Dr Janak Koirala would like to gratefully acknowledge Dr Tin Han Htwe and Dr Cristian A. Spiel, previous contributors to this topic.

Disclosures

THH and CAS declare that they have no competing interests.

Peer reviewers

Raymond J. Dattwyler, MD

Professor of Medicine and Microbiology/Immunology

Chief of Allergy, Immunology and Rheumatology

New York Medical College

Valhalla

Disclosures

RJD declares that he has no competing interests.

Ionita Catalina, MD

Assistant Professor of Neurology and Neurosurgery

SUNY at Buffalo

Stroke/Neurocritical Care

Millard Fillmore Gates Hospital - Kaleida Stroke Center

Buffalo

Disclosures

IC declares that she has no competing interests.

Graham Fry, MB, FRCSI, DTM&H

Lecturer in Tropical Medicine

University College Dublin

Medical Director

Tropical Medical Bureau

Ireland

Disclosures

GF declares that he has no competing interests.

Andras Lakos, MD, PhD

Physician

Centre for Tick-Borne Diseases

Budapest

Hungary

Disclosures

AL is an author of a reference cited in this topic.

Differentials
- Tickbite allergy
- Cellulitis
- Erythema multiforme
More Differentials
Guidelines
- 2020 guidelines for the prevention, diagnosis and treatment of Lyme disease
- Lyme disease
More Guidelines
Patient leaflets
Lyme disease
More Patient leaflets
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Lyme disease

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

known tick bite

erythema migrans

cardiac involvement

neurologic disease

arthritis

recurrent or persistent arthritis

Contributors

Authors

Janak Koirala, MD, MPH, FACP, FIDSA

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Raymond J. Dattwyler, MD

Disclosures

Ionita Catalina, MD

Disclosures

Graham Fry, MB, FRCSI, DTM&H

Disclosures

Andras Lakos, MD, PhD

Disclosures

Differentials

Guidelines

Patient leaflets

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

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