Lyme disease is a bacterial infection. It is passed from an infected deer tick that has attached and fed for more than 36 hours.
Lyme disease is caused by bacteria found in some deer ticks. The bacteria passes from the tick when it bites and feeds for a long time.
The bacteria can pass into the blood if the infection is not treated. This allows the bacteria to travel through the body and affect different areas.
Factors that may increase your chances of Lyme disease:
The symptoms of Lyme disease will be different in each person. Some people will not have symptoms. Those that do may have mild or severe symptoms.
The first sign may be a red rash. The rash starts as a small red spot at the site of the tick bite. It will then spread over the next few days or weeks to form a circular or oval-shaped rash. Sometimes, the rash resembles a bull's eye with a red ring around a clear area with a red center. The rash may cover a small dime-sized area or a wide area of the body.
This is an example of a Lyme disease rash shaped like a bull's eye. It may not always be this shape, nor will a rash always appear.
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In the first 3-30 days after the bite, if the infection has not spread you may notice:
These symptoms do not necessarily mean you have Lyme disease, even if you have spent time outdoors. See your doctor right away if you have these symptoms and think you have been exposed to a tick.
An infection that has begun to spread may cause the following symptoms in days to weeks after the bite:
Symptoms can develop months or years after the tick bite in untreated infections. These symptoms may occur regularly or intermittently and include:
Less common symptoms of late Lyme disease include:
The doctor may suspect Lyme disease based on the classic bulls-eye rash and knowledge of a tick bite. It will also help to know if you have been in an area with known Lyme disease.
The body may make antibodies against the infection about 2 to 4 weeks after the infection. A blood test may help look for these antibodies. The results of the blood test will be used along with symptoms and overall risk to make a diagnosis.
Lyme disease responds well to antibiotics. These medications can kill the bacteria.
Treatment may be given at home or in the hospital based on your illness. Antibiotics may be given by mouth or through an IV. Treatment may last from 5 to 28 days.
Some may have longer lasting issues after treatment such as chronic arthritis. A treatment plan will be made to help manage it. This may include a referral to a Rheumatologist. They focus on conditions that cause pain and swelling of joints, muscles, and bones.
To help reduce the chances of Lyme disease:
Insect repellent can help prevent tick bites. Repellents containing DEET can be applied to clothes and exposed skin. Repellents that have permethrin can be applied to pants, socks, and shoes, but not to skin. Repellents can cause eye irritation and skin reactions. Be sure to read the label for instructions on application, including:
Deer ticks are unlikely to pass the infection unless they are in contact with the skin for at least 36 hours. After spending time outdoors in a high risk area:
If you do find a tick, remove it by doing the following:
There are some steps that do not help. They may cause more problems.
If you have been bitten by a deer tick, watch for a rash to appear. This is especially important if Lyme disease is common in your area. A rash can occur in about 70 to 80% of infected persons. It often begins at the tick bite site.
Your doctor may recommend a single dose of an antibiotic if you had a tick bite in a high-risk area. This may reduce the risk of Lyme disease if taken within 72 hours after a tick bite.
Centers for Disease Control and Prevention
Lyme Disease Association of Canada
Lyme disease. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/lyme. Accessed January 29, 2021.
Lyme disease. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T114365/Lyme-disease. Accessed January 29, 2021.
Lyme disease. Family Doctor—American Academy of Physicians website. Available at: https://familydoctor.org/condition/lyme-disease. Accessed January 29, 2021.
Lyme disease. National Institute of Allergy and Infectious Diseases website. Available at: https://www.niaid.nih.gov/diseases-conditions/lyme-disease. Updated April 6, 2016. Accessed February 15, 2018.
Nadelman RB, Nowakowski J, Fish D, et al. Prophylaxis with single dose doxycycline for the prevention of Lyme disease after an Ixodes Scapularis tick bite. N Engl J Med. 2001;345(2):79-84.
Wormser GP, Dattwyler RJ, Shapiro ED, et al. The clinical assessment, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2006;43(9):1089-1134.
Last reviewed February 2021 by EBSCO Medical Review Board David L. Horn, MD, FACP Last Updated: 1/29/2021