Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted 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 validated methods.
Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, applying pesticides, and reducing tick habitat. The ticks that transmit Lyme disease can occasionally transmit other tick borne diseases as well.
Untreated Lyme disease can produce a wide range of symptoms, depending on the stage of infection. These include fever, rash, facial paralysis, and arthritis.
Early Signs and Symptoms (3 to 30 days after tick bite)
Fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes
Erythema migrans (EM) rash:
Occurs in approximately 70 to 80 percent of infected persons
Begins at the site of a tick bite after a delay of 3 to 30 days (average is about 7 days)
Expands gradually over a period of days reaching up to 12 inches or more (30 cm) across
May feel warm to the touch but is rarely itchy or painful
Sometimes clears as it enlarges, resulting in a target or “bull’s-eye” appearance
May appear on any area of the body
See examples of EM rashes
Later Signs and Symptoms (days to months after tick bite)
Severe headaches and neck stiffness
Additional EM rashes on other areas of the body
Arthritis with severe joint pain and swelling, particularly the knees and other large joints.
Facial palsy (loss of muscle tone or droop on one or both sides of the face)
Intermittent pain in tendons, muscles, joints, and bones
Heart palpitations or an irregular heart beat (Lyme carditis)
Episodes of dizziness or shortness of breath
Inflammation of the brain and spinal cord
Shooting pains, numbness, or tingling in the hands or feet
Problems with short-term memory