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 may include using natural insect repellent, removing ticks promptly, using preventative measures to try and reduce tick habitat. The ticks that transmit Lyme disease can occasionally transmit other tick-borne diseases as well.
Reported Cases of Lyme Disease
Lyme disease is diagnosed based on:
- Signs and symptoms
- A history of possible exposure to infected blacklegged ticks
Laboratory blood tests are helpful if used correctly and performed with validated methods. Laboratory tests are not recommended for patients who do not have symptoms typical of Lyme disease. Just as it is important to correctly diagnose Lyme disease when a patient has it, it is important to avoid misdiagnosis and treatment of Lyme disease when the true cause of the illness is something else.
Untreated Lyme disease can produce a wide range of symptoms, depending on the stage of infection. These include fever, rash, facial paralysis, and arthritis. Seek medical attention if you observe any of these symptoms and have had a tick bite, live in an area known for Lyme disease, or have recently traveled to an area where Lyme disease occurs.
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
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
- Nerve pain
- Shooting pains, numbness, or tingling in the hands or feet
- Problems with short-term memory
Patients treated with appropriate antibiotics in the early stages of Lyme disease usually recover rapidly and completely. Antibiotics commonly used for oral treatment include doxycycline, amoxicillin, or cefuroxime axetil. Patients with certain neurological or cardiac forms of illness may require intravenous treatment with drugs such as ceftriaxone or penicillin.
For detailed recommendations on treatment, consult the guidelines for treatment developed by the Infectious Diseases Society of America.
In a small percentage of cases, these symptoms can last for more than 6 months. Although sometimes called “chronic Lyme disease,” this condition is properly known as “Post-treatment Lyme Disease Syndrome” (PTLDS). The National Institutes of Health (NIH) has funded several studies on the treatment of Lyme disease which show that most patients recover when treated with a few weeks of antibiotics taken by mouth. For details on research into what is sometimes referred to as “chronic Lyme disease” and long-term treatment trials sponsored by NIH, visit the NIH Lyme Disease web site.