Lyme disease is an infection caused by the bite of an infected tick. The tick is so small that you may not notice the tick or its bite. Many ticks do not carry Lyme disease. Even if a tick is infected, it may not transfer the disease to you. An infected tick that is attached for less than 36 hours is less likely to transmit infection. For these reasons, most tick bites do not cause Lyme disease.
The disease often begins as a rash. If you don't get treatment, the infection can cause serious nerve or heart problems as well as a disabling type of arthritis (pain and swelling in one or more joints caused by inflammation).
Bacteria called Borrelia burgdorferi cause Lyme disease. The disease is spread to human beings by the bite of a tiny tick infected with the bacteria. These ticks are found in vegetation and on animals in woodlands, grasslands, and marshlands. Wild birds, mice, raccoons, and deer, as well as cats, dogs, horses, and cows, can carry the infected ticks. Ticks may climb on humans from leaf litter and low-lying vegetation in wooded, brushy, or grassy areas. Ticks cannot jump or fly.
People usually become infected during the summer, when they are more likely to be exposed to ticks. Hikers, campers, hunters, and people living in wooded or rural areas have a higher risk for Lyme disease.
This infection has been found on all continents except Antarctica. In the US the infection is more common in the northern states.
Lyme disease is hard to diagnose because its symptoms can vary greatly from person to person. The first symptoms may not even be noticed.
Untreated Lyme disease may progress through these 3 stages:
In the first month after a bite by an infected tick, a skin rash, called a bull's-eye or target rash, occurs at the site of your bite. The rash begins as a large red spot that may be flat or bumpy. The area of the rash feels warm, but it is not painful or itchy. The rash slowly spreads outward from the red center after several days, often in a circular pattern. The red color of the center usually fades, creating what is called a bull's-eye rash. Sometimes the rash may blister or scab in the center. The thigh, groin, and armpit are common sites for the rash, but it can appear anywhere.
Although most infected people develop a rash, you may not have this symptom, or you may overlook it.
You may feel like you have the flu, with such symptoms as:
Less common symptoms of early Lyme disease are:
Even if you don't get treatment, the early symptoms usually improve or go away within several weeks. However, fatigue, drowsiness, and sometimes vague muscle or joint pain may last for months after the rash has gone.
Several weeks to several months after the first symptoms appear, as many as 15% of infected people may develop problems with their nervous system. These problems may include:
The most serious of these complications--meningitis and encephalitis--fortunately are rare.
About 8% of infected people develop heart problems, such as carditis (inflammation of the heart) and problems with the rhythm of the heart.
During this second stage, you may have pain in your joints, tendons, muscles, or bones, usually without joint swelling. These symptoms usually disappear within a few weeks.
After several months of infection, about 60% of people start having arthritis, with joint pain and swelling. The knee is the joint most often affected.
In stage 3 you may have temporary bouts of arthritis or you may feel the arthritis all the time. You may have ongoing nervous system problems, but this is less likely. Symptoms of nervous system problems during stage 3 may include:
Lyme disease can be hard to diagnose. Your healthcare provider will ask about your symptoms and medical history. He or she will examine you.
You may have a blood test for Lyme disease. Or you and your provider may decide to start treatment without the test or before the test results are available.
If you were recently bitten by a tick, saving the tick may help your provider diagnose your symptoms or decide whether to treat you without testing.
Lyme disease is treated with antibiotics. Early treatment can help prevent possible complications. The choice of antibiotic may depend on such factors as the stage of the disease and whether your joints are inflamed.
If you are in stages 2 or 3 of the disease, you may also need other treatments. This is especially true if you have infection or inflammation of the heart, central nervous system, or joints.
Pregnant and nursing women: If you are pregnant and have Lyme disease, you may pass the disease to your baby. Although this happens rarely, you should call your healthcare provider right away if you are pregnant and are bitten by a tick or have symptoms of Lyme disease. Also, if you are a nursing mother and are bitten by a tick or have symptoms of infection, contact your provider for advice.
While you have the disease the symptoms may occur in cycles lasting a week or so.
In most cases the symptoms go away a few weeks or months after antibiotic treatment, but sometimes the symptoms last several years. For example, after treatment for stage 1 of the disease, you may have minor recurrences of headaches, muscle or joint pain, or fatigue, but eventually you should recover completely.
If the disease is not diagnosed and treated, the symptoms can last for several years, but they usually will gradually lessen.
Permanent problems caused by the disease vary from person to person and depend in part on your overall health condition. Meningitis and encephalitis, which can strike in stage 2, can be life threatening, but this is rare.
To help take care of yourself, follow the full course of treatment prescribed by your healthcare provider. You need to take all of your antibiotic therapy. Do not stop taking antibiotics because you start to feel better or your symptoms go away. If you have side effects from the antibiotic, call your provider about possibly getting a different prescription.
To avoid getting Lyme disease, follow these measures:
See your healthcare provider and take the tick with you, if you think you were bitten by a deer tick or you start having a rash or other symptoms within 4 weeks after you were bitten. If you do not have any symptoms of disease after 1 month, you can discard the tick.