Lyme Disease Symptoms and Diagnosis

Erythema Migrans. 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 at the site of the tick bite. The spot expands over a period of days or weeks, forming a circular or ovalshaped rash. Sometimes the rash resembles a bull's eye, appearing as a red ring surrounding a clear area with a red center. The rash, which can range in size from that of a dime to the entire width of a person's back, appears within a few weeks of a tick bite and usually occurs at the site of a bite. As infection spreads, rashes can appear at different sites on the body.

Erythema migrans is often accompanied by symptoms such as fever, headache, stiff neck, body aches, and fatigue. Although these flu-like symptoms may resemble those of common viral infections, Lyme disease symptoms tend to persist or may occur intermittently.

Arthritis. After several months of being infected by B. burgdorferi, slightly more than half of those people not treated with antibiotics develop recurrent attacks of painful and swollen joints that last a few days to a few months. The arthritis can shift from one joint to another; the knee is most commonly affected. About 10 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, or 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.

Nervous system abnormalities usually develop several weeks, months, or even years following an untreated infection. These symptoms often last for weeks or months and may recur.

Heart Problems. Fewer than one out of ten Lyme disease patients develops heart problems, such as an irregular heartbeat, which can be signalled by dizziness or shortness of breath. These symptoms rarely last more than a few days or weeks. Such heart abnormalities generally surface several weeks after infection.

Other Symptoms. Less commonly, 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.


How Lyme Disease Is Diagnosed

Lyme disease may be difficult to diagnose because many of its symptoms mimic those of other disorders. In addition, the only distinctive hallmark unique to Lyme disease-the erythema migrans rash-is absent in at least one-fourth of the people who become infected. The results of recent studies indicate that an infected tick must be attached to a person's skin for at least 2 days to transmit the Lyme bacteria. Although a tick bite is an important clue for diagnosis, many 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 physician will rely on a detailed medical history and a careful physical examination for essential clues to diagnosis, with laboratory tests playing a supportive role.

Most Common Symptoms of Lyme Disease Early Infection EM Rash (erythema migrans) Muscle and joint aches Headache Fever Fatigue Early Disseminated Infection Multiple EM lesions Facial paralysis (Bell's palsy) Meningitis Radiculitis (numbness, tingling, burning) Brief episodes of joint pain and swelling Late Infection Arthritis, intermittent or chronic Encephalopathy (mild to moderate confusion) Less Common Symptoms of Lyme Disease Heart abnormalities Eye problems such as conjunctivitis Chronic skin disorders Encephalomyelitis (limb weakness, motor coordination)

Blood Tests. Unfortunately, the Lyme disease microbe itself is difficult to isolate or culture from body tissues or fluids. Most physicians look for evidence of antibodies against B. burgdorferi in the blood to confirm the bacterium's role as the cause of a patient's symptoms. Antibodies are molecules or small substances tailor-made by the immune system to lock onto and destroy specific microbial invaders.

Some patients experiencing nervous system symptoms may also undergo a spinal tap. Using this procedure, doctors can detect brain and spinal cord inflammation and can look for antibodies or genetic material of B. burgdorferi in the spinal fluid.

The inadequacies of the currently available diagnostic tests may prevent physicians from firmly establishing whether the Lyme disease bacterium is causing a patient's symptoms. In the first few weeks following infection, 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 may also prevent antibodies from reaching detectable levels, even though the Lyme disease bacterium is the cause of the patient's symptoms.

The antibody test used most often is called an ELISA test. When an ELISA is positive, it should be confirmed with a second, more specific test, called a Western blot.

Physicians 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 time of year, history of a tick bite, the patient's symptoms, and a thorough ruling out of other diseases that might cause those symptoms. Doctors may consider such factors as an initial appearance of symptoms during the summer months when tick bites are most likely to occur, and outdoor exposure in an area where Lyme disease is common.

New Tests Under Development. To improve the accuracy of Lyme disease diagnosis, NIH-supported researchers are developing a number of new tests that promise to be more reliable than currently available procedures.

NIH scientists are developing tests that use the highly sensitive genetic engineering technique, known as polymerase chain reaction (PCR), to detect extremely small quantities of the genetic material of the Lyme disease bacterium in body tissues and fluids.

A bacterial protein, outer surface protein (Osp) C, is proving useful for the early detection of specific antibodies in people with Lyme disease.

• What is Lyme Disease?
• Treatment
• Prevention