What is Lyme disease?
Lyme disease, the most common tick-borne illness in North America and Europe, is an infection caused by the bacterium Borrelia burgdorferi.
Ticks are arachnids, like spiders, and feed by imbedding their mouthparts into the host’s skin and sucking the host’s blood. They pick up the bacteria from infected mice and deer on which they feed at various times in their two-year life cycle.
In order to transmit the bacteria to humans, ticks must be attached to the skin and must feed for at least 24 to 48 hours. The bacteria then enter the skin through the bite and eventually make their way into the bloodstream.
It is important to know that the majority of tick bites don’t result in Lyme disease. However, it is still important to remove the tick as soon as you find it.
It’s very hard to see most ticks. Immature ticks, which are called nymphs, are about the size of a poppy seed. Adult ticks are about the size of a sesame seed. Because the ticks are so difficult to see, many people do not realize they have been bitten. That is why it is important to know the symptoms of Lyme disease.
What are the signs and symptoms of Lyme disease?
Lyme disease occurs in three stages, and can affect different systems in your body. People with Lyme disease often do not experience all of the symptoms of all of the stages.
Stage One usually starts with circular rash, which may occur within one to two weeks of infection but could possibly develop as much as thirty days after the tick bite. The rash, known as erythema migrans, typically has a characteristic “bull’s-eye” appearance and can appear anywhere on the body, not just at the site of the bite. There is usually a red spot in the center surrounded by clear skin and then a red expanding ring. It may also appear as an expanding solid red ring. Typically, there are few symptoms, though the rash may feel a bit warm to the touch.
The rash usually resolves in about a month. Although this rash is considered typical of Lyme disease, many people may never develop the rash.
Along with the rash, there may be flu-like symptoms such as swollen lymph nodes, fatigue, headache, and muscle aches. If the infection is not identified and is left untreated, these initial symptoms may resolve spontaneously. In some people at this point, the infection can spread to other parts of the body.
People who are bitten and not infected, still could develop a redness at the site of the bite if they are allergic to tick saliva. The redness usually fades within a week. This is not the same as erythema migrans, which tends to expand and become redder over time and can appear anywhere on the body.
Symptoms of the second stage of Lyme disease usually appear within several weeks after the tick bite, even in someone who has not developed the initial rash. Fatigue and achiness may be accompanied by headache, swelling and pain in the large joints, and general malaise. Lyme disease can also affect the heart and cause chest discomfort and an abnormal heart rhythm. It can affect the central nervous system and cause numbness and tingling in the extremities and possibly even cause a nerve disorder known as Bell’s Palsy that affects the muscles on one side of the face. Again, if the infection goes untreated at this point, it can progress to the third and last stage of Lyme disease.
Advanced Lyme disease can appear any time from weeks to years after the initial infection. They may include arthritis – particularly in the knees – and memory issues. The memory issues typically occur in adults only.
Diagnosing Lyme disease
It can be difficult to diagnose Lyme disease because of the variety of symptoms and the fact that they don’t appear consistently with every case. Blood tests can be effective, but may not detect the infection in the first stages.
Because the symptoms of Lyme disease are similar to those of other diseases, it is best to speak with your health care provider to decide on the best plan of action to evaluate your symptoms and discuss your concerns.
What are the tests that help to diagnose Lyme disease?
Lab tests to identify antibodies to the bacterium may be used to help confirm the diagnosis. These tests are most reliable a few weeks after an infection, after your body has time to develop antibodies. They include:
- Enzyme-linked immunosorbent assay (ELISA) test. This is the test most often used to detect Lyme disease. The test detects antibodies to Borrelia burgdorferi. However, because it can sometimes provide false-positive results, it is not used as the sole basis for diagnosis.
- Western blot test. If the ELISA test is positive, this test is usually done to confirm the diagnosis. The Western blot detects antibodies to several proteins of Borrelia burgdorferi.
- Polymerase chain reaction (PCR). This test helps detect bacterial DNA in fluid drawn from an infected joint. It is not as effective at detecting infection of blood or urine. It is used for people who may have chronic Lyme arthritis. It may also be used to detect persistent infection in the cerebrospinal fluid of people who have nervous system symptoms.
How is Lyme disease treated?
Lyme disease is usually treated with a two- to four-week course of antibiotics. The antibiotics may be oral or intravenous depending on the clinical stage of the disease. Cases of Lyme disease that are diagnosed quickly and treated with antibiotics almost always have a good outcome. A person should be feeling back to normal within several weeks after being treated.
Antibiotic treatment at the time of a tick bite when there are not symptoms or signs of the disease is usually not necessary. Typically, the infection is treated in the first stage primarily based on the symptoms and bull’s-eye rash and without confirming blood tests. Long-term antibiotic treatment for Lyme disease is also controversial. These issues are best discussed with your health care provider.
Can Lyme disease be prevented?
There is no way to prevent the disease, but you can be hyper vigilant about protecting yourself, especially when you are in areas of higher risk for ticks. If you are active outdoors, there are ways to protect yourself against tick bites. These precautions also help protect you from other insects. See “Insect Bites and Stings” on this website.
Always check yourself for ticks thoroughly after being outside.
- Check your pets for ticks as well, especially after they have been in high-risk areas.
- Wear shoes or boots that cover your entire foot.
- Wear long-sleeved shirts and long pants. Tuck your pant legs into your shoes, boots, or socks to prevent ticks from crawling up your legs.
- Wear lighter clothes to make ticks easier to identify.
- Always wash your clothes and hair after being in high-risk areas.
- If you use insect repellents, be sure to strictly adhere to the manufacturer’s instructions, and follow these guidelines:
- Do not use insect repellents (especially those containing DEET) on young children, especially on their hands.
- The most common insecticide is DEET, which should not be applied more than once a day. Using DEET more than once a day could cause a toxic reaction. Concentrations vary from less than 10% to over 30%. The higher the concentration, the longer the duration of action. Never use any preparation that contains more than 30% DEET. Select the lowest effective concentration based on the amount of time you will be outdoors.
- Do not use products that combine repellant with sunscreen, as sunscreen needs to be reapplied every few hours.
- Be sure to wash off repellant with soap and water at the end of the day.
- Picaridin is an alternative to DEET that is widely used in Europe. Concentrations of 5-10% are appropriate for use. These repellants are effective in preventing bites by mosquitoes, ticks, fleas, chiggers, and biting flies, but are ineffective in preventing stings.
- If you have long hair, pull it up. Wear a hat.
- Avoid sitting on the grass or ground, and avoid leaning up against trees, and tramping through bush.
- Keeping your yard free of any piles of leaves or brush.
How to remove a tick
To remove an imbedded tick, using tweezers, grasp the tick as closely to the skin as possible. Gently tug on the tick. Do not twist or “unscrew” the tick. Don’t worry if the head remains imbedded in the skin. It will eventually come out on its own. Clean the area with an antiseptic.
Can a person get Lyme disease more than once?
It is possible for a person to contract Lyme disease more than once, as the disease does not provide immunity against further infection. It is important to be ever-vigilant in the prevention of tick bites.