What is Lyme disease?

Lyme disease is a bacterial disease caused by Borrelia burgdorferi, a spiral-shaped bacterium. The 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. Further investigations showed that tiny deer ticks infected with the bacterium were responsible for the outbreak of arthritis. Ordinary "wood ticks" and "dog ticks" do not carry the infection.

What are the symptoms of Lyme disease?

In most people, the first symptom of Lyme disease is a red rash known as erythema migrans. The rash starts as a small red spot that expands over a period of days or weeks, forming a circular, triangular, or oval-shaped rash. Because it appears as a red ring that surrounds a clear center area, the rash may resemble a bull's eye.

The rash can range in size from that of a dime to the entire width of a person's back. It appears within 1 to 4 weeks of the tick bite, usually at the site of a bite. As infection spreads, several rashes can appear at different sites on the body.

The rash may be accompanied by symptoms such as fever, headache, stiff neck, body aches, and fatigue, which can last from a few days to a few weeks.

If the infection goes untreated, a majority of those affected may develop repeated attacks of painful and swollen joints that last a few days to a few months.

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.

Memory loss, difficulty with concentration, and a change in mood or sleeping habits have also been associated with Lyme disease. However, Lyme disease rarely causes these nonspecific symptoms on an ongoing basis.

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 is Lyme disease diagnosed?

Lyme disease may be difficult to diagnose because many of its symptoms mimic those of other disorders. In addition, the only distinctive symptom of Lyme disease -- the red rash -- is absent or is unnoticed in at least one-fourth of those who become infected. Also, many patients can't recall having been bitten by a tick, because the tick is tiny and its bite is usually painless.

If no rash is present, a physician will rely on a detailed medical history, a careful physical examination, and laboratory tests for essential clues to a diagnosis.

How is Lyme disease treated?

Nearly all Lyme disease patients can be effectively treated with antibiotics. In general, the sooner such therapy is initiated following infection, the quicker and more complete the recovery. Antibiotics such as doxycycline or amoxicillin, taken orally (by mouth) for 2 to 4 weeks, can speed the resolution of symptoms and usually prevent subsequent symptoms such as arthritis or neurological problems.

Can Lyme disease be prevented?

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, few tick bites take place during winter months.

Deer ticks are most often found in wooded areas and nearby grasslands. They are especially common where the two areas merge, including neighborhood yards where deer occasionally roam. Ticks do not survive long on sunny lawns; they dry out quickly and die. Although only about 1 percent of all deer ticks are infected with the Lyme disease bacterium, in some areas more than half of them may harbor the microbe.

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.

The following tips can help you avoid tick bites:

  • Walk in the center of trails to avoid picking up ticks from overhanging grass and brush.
  • Minimize skin exposure to both ticks and insect repellents by wearing long pants and long-sleeved shirts that fit tightly at the ankles and wrists.
  • Wear a hat, tuck your pant legs into socks, and wear shoes that leave no part of your feet exposed.
  • Wear light-colored clothing to make it easier to detect ticks.
  • After outdoor activity in an "at risk" area, always do a tick check and then shower, scrubbing with a washcloth.
  • Get rid of any ticks on your clothes by putting them in the dryer for 15 minutes. This will kill any ticks attached to the clothes by drying them.
  • Pets may bring ticks into the home.
  • To repel ticks, you may want to spray your clothing with permethrin, an insecticide 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.

However, be aware that these repellents can cause serious side effects, especially when applied to the skin repeatedly and in high concentrations. Infants and children may be especially at risk for adverse reactions to DEET. Read the directions carefully.

What should I do if I am bitten by a tick?

If you experience a tick bite, 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 (such as Vaseline®), or cigarette butts to remove the tick.
  • DO NOT squeeze the tick's body with your fingers or tweezers.

© Copyright 1995-2014 The Cleveland Clinic Foundation. All rights reserved.

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: 11/26/2014...#9161