Lyme Disease Overview
Lyme disease was first recognized in 1975 after researchers investigated why unusually large numbers of children were being diagnosed with juvenile rheumatoid arthritis in Lyme, Connecticut, and two neighboring towns. The investigators discovered that most of the affected children lived near wooded areas likely to harbor ticks.
Further investigations resulted in the discovery that tiny deer ticks infected with a spiral-shaped bacterium or spirochete (which was later named Borrelia burgdorferi ) were responsible for the outbreak of arthritis in Lyme. Ordinary "wood ticks" and "dog ticks" did not carry the infection.
The white-tailed deer is the normal host for B. burgdorferi. Humans are only coincidental hosts. The recent growth of the deer population in the northeast and the building of suburban developments in rural areas where deer ticks are commonly found have probably contributed to the increasing number of people with the disease. Ticks might also be found in grassy areas and yards, as well as wooded areas.
The number of reported cases of Lyme disease, as well as the number of geographic areas in which it is found, has been increasing. Lyme disease has been reported in nearly all states in this country, although most cases are concentrated in the coastal northeast, Mid-Atlantic States, Wisconsin, Minnesota, and northern California. Lyme disease is also found in large areas of Asia and Europe. Recent reports suggest that it is present in South America, too.
Symptoms of Lyme disease
The most common symptoms of Lyme disease include:
Rash — In most people, the first symptom of Lyme disease is a red rash known as erythema migrans (EM). The telltale rash starts as a small red spot that expands over a period of days or weeks, forming a circular, triangular, or oval-shaped rash. Sometimes the rash resembles a bull's eye because it appears as a red ring surrounding a central clear area. The rash, which can range in size from that of a dime to the entire width of a person's back, appears within one to four weeks of a tick bite, usually occurring at the site of the bite. If untreated, the rash might eventually appear at different sites on the body. EM is often asymptomatic, but might be accompanied by symptoms such as fever, headache, stiff neck, body aches, and fatigue. These flu-like symptoms might resemble those of common viral infections and usually resolve within days or a few weeks.
Arthritis — After several weeks to months of being infected with the bacteria and not treated with antibiotics, the individual may develop recurrent attacks of painful swollen joints that last anywhere from a few days to a few months. The arthritis usually affects weight-bearing joints, with the knee the most commonly affected. About 10 percent to 20 percent of untreated patients will go on to develop chronic arthritis.
Neurological symptoms — Lyme disease can also affect the nervous system, causing symptoms such as stiff neck and severe headache (meningitis), temporary paralysis of facial muscles (Bell's palsy), numbness, pain or weakness in the limbs, and poor motor coordination. More subtle changes, such as memory loss, difficulty with concentration, and a change in mood or sleeping habits, have also been associated with Lyme disease. However, these non-specific symptoms are rarely caused by Lyme disease. Nervous system abnormalities usually develop several weeks, months, or even years following an untreated infection. These symptoms often last for weeks or months and might recur. Patients with neurologic disease usually have an eventual total return to normal function.
Heart problems — Approximately one of 20 untreated Lyme disease patients develop heart problems, such as an irregular, slow heartbeat, which can be signaled by dizziness or shortness of breath. These symptoms might persist for a few days or weeks before resolving.
Other symptoms — Less common symptoms of Lyme disease can result in eye inflammation, hepatitis, and severe fatigue, although none of these problems is likely to appear without other Lyme disease symptoms being present.
Diagnosing Lyme disease
Lyme disease might be difficult to diagnose because many of its symptoms mimic those of other conditions. In addition, the only distinctive hallmark unique to Lyme disease — the erythema migrans rash — is absent or is unnoticed in at least one-fourth of the people who become infected. Although a tick bite is an important clue for diagnosis, most patients cannot recall having been bitten recently by a tick. This is not surprising, because the tick is tiny, and a tick bite is usually painless.
When a patient with possible Lyme disease symptoms does not develop the distinctive rash, a doctor will rely on a detailed medical history and a careful physical examination for essential clues to an alternative diagnosis. Laboratory tests play a supportive role.
Blood tests — Unfortunately, the Lyme disease microbe itself is difficult to isolate or culture from body tissues or fluids. Doctors will look for evidence of antibodies against B. burgdorferi in the blood to confirm prior infection with the bacterium. Antibodies are molecules or small substances tailor-made by the immune system to lock onto and destroy specific microbial invaders. The presence of antibodies, however, does not prove that the bacterium is the cause of a patient's symptoms. The presence of specific antibodies suggests a prior infection, which might or might not still be active.
Spinal tap — Some patients experiencing nervous system symptoms might also undergo a spinal tap. A spinal tap is a procedure during which a sample of spinal fluid is removed from the spinal canal for the purpose of testing in a laboratory. Through this procedure, doctors can detect brain and spinal cord inflammation, and can look for antibodies in the spinal fluid.
In the first few weeks following infection (when the rash first appears), antibody tests are not reliable because a patient's immune system has not produced enough antibodies to be detected. Antibiotics given to a patient early during infection might also prevent antibodies from reaching detectable levels, even though the Lyme disease bacterium is the cause of the patient's symptoms.
Because some tests cannot distinguish Lyme disease antibodies from antibodies to similar organisms, patients might test positive for Lyme disease when their symptoms actually stem from other problems. A lack of standardization of antibody tests and poor quality control might also contribute to inaccuracies in test results.
Because of these difficulties, doctors must rely on their clinical judgment in diagnosing someone with Lyme disease, even though the patient does not have the distinctive erythema migrans rash. Such a diagnosis would be based on the history of a tick bite or exposure to an environment that could result in the tick bite, the patient's symptoms, a thorough ruling out of other diseases that might cause those symptoms, and other implicating evidence. This evidence could include such factors as an initial appearance of symptoms during the summer months when tick bites are most likely to occur.
Treating and managing Lyme disease
Nearly all Lyme disease patients can be effectively treated with an appropriate course of antibiotic therapy. In general, the sooner such therapy is begun following infection, the quicker and more complete the recovery. Antibiotics such as doxycycline or amoxicillin taken orally for two to four weeks can speed the healing of the erythema migrans rash and usually prevent subsequent symptoms such as arthritis or neurological problems. There is no compelling evidence that prolonged antibiotic therapy is more effective than two weeks of therapy. Unnecessarily prolonged antibiotic use could have serious side effects.
Patients younger than 9 years old, or pregnant or lactating women with Lyme disease, are treated with amoxicillin or penicillin because doxycycline can stain the permanent teeth developing in young children or unborn babies. Patients allergic to penicillin are given erythromycin or related antibiotics.
People with Lyme disease who have neurological symptoms might be treated with an antibiotic given intravenously for a month or less. Most patients experience full recovery.
Lyme arthritis resolves in most patients within a few weeks or months following antibiotic therapy. Some Lyme disease patients who are untreated for several years might be cured of their arthritis with the proper antibiotic regimen. Antibiotics given by mouth are very effective. Therefore, intravenous antibiotics are only rarely indicated or needed.
Doctors prefer to treat Lyme disease patients experiencing heart symptoms with antibiotics such as ceftriaxone, cefotaxime, or penicillin given intravenously for about two weeks. If these symptoms persist or are severe enough, patients might also be treated with corticosteroids or given temporary internal cardiac pacemakers. People with Lyme disease rarely experience long-term heart damage.
Following treatment for Lyme disease, some people still have persistent fatigue and achiness. This general malaise can take months to slowly disappear, although it generally does so spontaneously without the use of additional antibiotic therapy.
Successful treatment of a bout with Lyme disease is no guarantee that the illness will be prevented in the future. The disease can strike more than once in the same individual if he or she is bitten by another tick and re-infected with the Lyme disease bacterium.
Preventing Lyme disease
Fortunately, the cause of Lyme disease is known and the disease can be prevented. Essential to prevention is the avoidance of deer ticks. Although generally only about 1 percent of all deer ticks is infected with the Lyme disease bacterium, in some areas more than half of them harbor the microbe.
Deer ticks are most often found in wooded areas and nearby grasslands, and are especially common where the two areas merge, including neighborhood yards where deer occasionally roam. Ticks do not survive long on sunny lawns where they dry out quickly and die.
Most people with Lyme disease become infected during the late spring, summer, and early fall when immature ticks are out feeding. Except in warm climates, deer ticks bite few people during winter months.
To help prevent tick bites, people entering tick-infested areas should walk in the center of trails to avoid picking up ticks from overhanging grass and brush.
To minimize skin exposure to both ticks and insect repellents, people in tick-infested areas should wear long pants and long-sleeved shirts that fit tightly at the ankles and wrists. As a further safeguard, people should wear hats, tuck pant legs into socks, and wear shoes that leave no part of the feet exposed. To make it easy to detect ticks, people should wear light-colored clothing. Pets might also bring ticks into the home.
To repel ticks, people can spray their clothing with the insecticide permethrin, which is commonly found in lawn and garden stores. Insect repellents that contain a chemical called DEET can also be applied to clothing or directly onto skin. Although highly effective, these repellents can cause some serious side effects, particularly when high concentrations are used repeatedly on the skin. Infants and children might be especially at risk for adverse reactions to DEET. Read directions carefully.
After outdoor activity in an area "at risk," one should always do a tick check. Look for new freckles. A shower using a brief scrub with a washcloth might dislodge some ticks. Remember that ticks take many hours to attach themselves and up to two days to finally feed and spread the infection. To get rid of ticks in your clothes, simply put them in your dryer for 15 minutes. This will kill any ticks attached to the clothes by drying them.
Pregnant women should be especially careful to avoid ticks in Lyme disease areas because the infection can be transferred to the unborn child. Such a prenatal infection can make the woman more likely to miscarry.
If an infected tick bites, it will not transmit the infection until it has had the opportunity to have its blood meal. It might require up to 36 hours before infection is transmitted; thus there is value in inspecting your body after outdoor activities in areas where Lyme disease is known to occur. Newly attached ticks can be easily removed before they transmit the infection.
Prophylactic antibiotics are not generally utilized following all tick bites, but might be used in some special circumstances. A recent study showed that such preventive use of antibiotics might be very effective.
If a tick bites you, the best way to remove it is by taking the following steps:
- Tug gently but firmly with blunt tweezers near the "head" of the tick until it releases its hold on the skin.
- To lessen the chance of contact with the bacterium, avoid crushing the tick's body or handling the tick with bare fingers.
- Swab the bite area thoroughly with an antiseptic to prevent bacterial infection.
- DO NOT use kerosene, petroleum jelly, or a cigarette butt.
- DO NOT squeeze the tick’s body with your fingers or tweezers.
For more information
American Lyme Disease Foundation
P.O. Box 466
National Institutes of Health
Bethesda, MD 20892
© Copyright 1995-2010 The Cleveland Clinic Foundation. All rights reserved.
Can't find the health information you’re looking for?
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 7/28/2010...#9161