KEY POINTS

• Lyme disease is a bacterial infection spread to people through the bite of blacklegged ticks.
• Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart, and the nervous system.
• Lyme disease is most common in the Northeast, mid-Atlantic, and upper-Midwest regions of the United States.

Overview

In the United States, Lyme disease is caused by the bacterium Borrelia burgdorferi and rarely, Borrelia mayonii. It occurs most commonly in the Northeast, mid-Atlantic, and upper-Midwest regions. Lyme disease bacteria are spread to humans through the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks. Laboratory testing is helpful if used correctly and performed with FDA-cleared tests. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics.

Signs and symptoms

Untreated Lyme disease can produce a wide range of symptoms, depending on the stage of infection. These include fever, rash, facial paralysis, an irregular heartbeat, and arthritis.

How it spreads

Lyme disease bacteria causing human infection in the United States are spread to people by blacklegged (Ixodes) ticks.

Prevention

Prevent tick bites

The best defense against Lyme disease is to prevent tick bites. This will reduce your risk of other tickborne diseases as well.

What to do after a tick bite

Remove attached ticks as soon as possible. Depending on the type of tick and how long it was attached, antibiotic prophylaxis might help to prevent Lyme disease. Call your doctor if you develop fever, rash, or other symptoms.

Testing and diagnosis

CDC recommends the use of FDA-cleared antibody tests for laboratory diagnosis of Lyme disease.