Lyme disease is the most common tick-borne infection in North America. It is caused by Borrelia burgdorferi, which is a bacteria transmitted to humans through the bite of the tick species Ixodes scapularis and Ixodes pacificus. To infect the host, these deer ticks must be attached to the skin for at least 36 hours. The likelihood of Lyme disease transmission is higher if a tick bite occurs in an area where Lyme disease is most common, most notably the northeastern (Virginia to Maine) and north-central (Wisconsin and Minnesota) states. The west coast, particularly Northern California, is also known to have a greater number of tick infections. Thousands of cases are reported each year in the United States.
Typical symptoms of Lyme disease usually begin within a few weeks (3-30 days) of a tick bite and include fever, headache, fatigue, chills, body aches, swollen glands, and a rash. The course of illness is similar to influenza but usually occurs during late spring and early summer months when ticks are more prevalent. The rash, which occurs in 70-80 percent of those infected, begins at the site of the tick bite and is red and circular. It gradually expands over a period of several days and often begins to have the appearance of a “bull’s-eye.”
Lyme disease is diagnosed by physical findings including rash and a history of exposure to ticks. Laboratory testing is sometimes helpful but may not always be conclusive, depending on the state of the disease. Antibodies against Lyme disease may take up to 4-6 weeks to develop, so tests performed before this time may be negative even if a person is infected.
Antibiotics are used to treat confirmed Lyme disease and suspected cases. A vast majority of patients recover quickly. While doxycycline typically has been avoided in young children (due to concerns of teeth staining), it is the most effective drug for the treatment of Rocky Mountain spotted fever (RMSF) and other tick-borne illnesses such as ehrlichiosis. In 2010, the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) Committee on Infectious Diseases recommended doxycycline as the first-line treatment for these infections in patients of all ages. The Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR) are currently working on new guidelines for Lyme disease management and will likely update this antibiotic recommendation as well.
Untreated Lyme disease can cause problems with the skin, joints, nervous system, and heart.
The best treatment for Lyme disease is prevention. Wear long-sleeved shirts and long pants while walking in the woods and avoid grassy or bushy areas. Use an insect repellent containing (no more than 30 percent) DEET on exposed skin. It is important to check the entire body daily for ticks, paying special attention to the scalp, armpits, and groin. Carefully remove ticks as soon as possible with fine-tipped tweezers and never try to burn a tick away from the skin.
Reviewed by Dr. Sara Connolly, April 2019
- Lyme disease is most common in endemic areas of the United States: northeastern and north-central states.
- Typical symptoms of Lyme disease include fever, headache, fatigue, chills, body aches, swollen glands, and a characteristic “bulls-eye” rash.
- Antibiotics are used to treat suspected or confirmed cases of Lyme disease, but prevention is the best treatment.