by Mary Calvagna, MS
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. The spread of the infection can cause a number of symptoms, ranging from mild to severe.
Risk Factors TOP
Factors that increase your risk 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.
Early Disseminated Infection
An infection that has begun to spread may cause the following symptoms in days to weeks after the bite:
Symptoms can develop in 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:
A doctor may be able to diagnose Lyme disease based on your symptoms and the history of a tick bite.
After four weeks of Lyme disease, your body may create antibodies against the infection. Your doctor may look for these antibodies with a blood test. 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. Antibiotics used most often include:
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 injection.
To relieve pain from chronic arthritis you doctor may recommend:
Try the following to help prevent 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 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. It may take about one month after the bite for the rash to show.
If you have a tick bite and live in a high-risk area, your doctor may recommend a dose of the antibiotic doxycycline. 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 less than 8 years old. This prevention step is only used in people older than 8 years.
The risk of catching Lyme disease after a single tick bite is low. Many experts do not recommend preventive antibiotic treatment.
Centers for Disease Control and Prevention
Lyme Disease Foundation
Communicable Disease Control
Public Health Agency of Canada
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1/4/2011 DynaMed's Systematic Literature Surveillance https://dynamed.ebscohost.com/about/about-us: 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 October 2012 by Michael Woods, MD
Last Updated: 10/31/2012