Lyme disease is a bacterial infection. The infection is spread from the bite of an infected deer tick.
Lyme disease is caused by bacteria found in some deer ticks. An infected tick passes Lyme disease to humans through its bite.
If untreated, the bacteria can pass into the blood. The blood will carry it through the body. The bacteria may then settle in various body tissues.
Factors that increase your chance of Lyme disease include:
The symptoms of Lyme disease will be different in each person. They can also range from mild to severe.
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.
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:
Lyme disease may be diagnosed based on your symptoms and the history of a tick bite.
After 4 weeks of Lyme disease, your body may create antibodies against the infection. A blood test may help look for these antibodies. The blood test cannot confirm or rule out Lyme disease. Instead, the results of the blood test will be used in combination with your symptoms and personal history to make a diagnosis.
Lyme disease responds well to antibiotics. These medications can kill bacteria.
The length of your antibiotic treatment will depend on your condition. You may need to take them for 10 days to 3 weeks or more. You may be given the antibiotics by mouth or by IV.
To relieve pain from chronic arthritis you doctor may recommend:
To help reduce the chance of Lyme disease:
If you live or are visiting northeastern, northwestern, mid-Atlantic, or upper north-central regions of the United States and northwestern California:
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 24 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, especially if you live in an area where Lyme disease is common, you should watch for a rash to appear. A rash can occur in about 70-80% of infected persons and generally begins at the tick bite site. The rash may appear within 3-30 days, usually before the onset of fever. The rash is usually the first sign of infection, is usually circular, and is called erythema migrans (EM). Some may develop additional EM lesions on other parts of the body.
If you have a tick bite and live in a high-risk area, your doctor may recommend a dose of antibiotic. This may reduce the risk of contracting Lyme disease if taken within 72 hours after a tick bite. However, this antibiotic can have serious side effects in children younger than 8 years old. This prevention step is only used in people older than 8 years of age.
The risk of getting Lyme disease after a single tick bite is low. Many experts do not recommend preventive antibiotic treatment.
Centers for Disease Control and Prevention
Public Health Agency of Canada
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1/4/2011 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T114365/Lyme-disease: Warshafsky S, Lee DH, Francois LK, Nowakowski J, Nadelman RB, Wormser GP. Efficacy of antibiotic prophylaxis for the prevention of Lyme disease: an updated systematic review and meta-analysis. J Antimicrob Chemother. 2010;65(6):1137-1144.
Last reviewed March 2017 by EBSCO Medical Review Board David L Horn, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.