You've probably heard of Lyme disease. It's often associated with heavily wooded or grassy areas where mice and deer live. Lyme disease is most common in the northeastern United States and the Pacific Northwest, as well as the northern midwestern states.

What Is Lyme Disease?

Lyme disease is an infection caused by the bacterium Borrelia burgdorferi. This bacterium is usually found in animals like mice and deer. It can be carried to people from these animals by Ixodes ticks (known as black-legged or deer ticks). These ticks pick up Borrelia burgdorferi when they bite infected animals and then infect humans by biting them and passing the bacteria into the person's bloodstream.

Sound gross? Maybe. But you can be sure that you won't witness this process: It's very hard to see the ticks themselves. Immature ticks, or nymphs, are about the size of a poppy seed. Adult ticks are about the size of a sesame seed.

Because the ticks are hard to find, it helps to be aware of the symptoms of Lyme disease. It's easy to overlook a tick bite. Many people who get Lyme disease don't remember being bitten. The good news is that most tick bites don't result in Lyme disease.

What Are the Signs & Symptoms?

Lyme disease can affect different body systems, such as the nervous system, joints, skin, and heart. The symptoms of Lyme disease are often described as happening in three stages. Not everyone experiences all of these stages, though:

1. Often, the first sign of infection is a circular rash. This rash appears within 1-2 weeks of infection but may develop up to 30 days after the tick bite. The rash often has a characteristic "bull's-eye" appearance, with a central red spot surrounded by clear skin that is ringed by an expanding red rash. It may also appear as an expanding ring of solid redness. It may be warm to the touch and is usually not painful or itchy. The bull's-eye rash may be more difficult to see on people with darker skin tones, where it may take on a bruise-like appearance.
   
   The rash usually goes away in about a month. Although this rash is considered typical of Lyme disease, many people never develop it.
2. Along with the rash, a person may experience flu-like symptoms such as swollen lymph nodes, fatigue, headache, and muscle aches. Left untreated, symptoms of the initial illness may go away on their own. But in some people, the infection can spread to other parts of the body. Symptoms of this stage of Lyme disease usually appear within several weeks after the tick bite, even in someone who has not developed the initial rash. The person may feel very tired and unwell, or may have more areas of rash that aren't at the site of the bite.
   
   Lyme disease can affect the heart, leading to an irregular heart rhythm or chest pain. It can spread to the nervous system, causing facial paralysis (Bell's palsy) or tingling and numbness in the arms and legs. It can start to cause headaches and neck stiffness, which may be a sign of meningitis.
3. The last stage of Lyme disease can occur if the early stages of the disease were not detected or appropriately treated. Symptoms of late Lyme disease can appear any time from weeks to years (average of 6 months) after an infectious tick bite, and in children and teens is almost always in the form of arthritis, particularly in the knees or other large joints.

Having such a wide range of symptoms can make Lyme disease difficult for doctors to diagnose. Fortunately, there's a blood test that looks for evidence of the body's reaction to Lyme disease.

When Should I Call My Doctor?

If you think you may be at risk for Lyme disease or a tick has bitten you, contact your doctor. Although conditions other than Lyme disease can cause the symptoms mentioned above, it's always a good idea to discuss symptoms with your doctor. That way you can get further evaluation and treatment if necessary, before the disease progresses too far. This is especially true if you develop a red-ringed rash, prolonged flu-like symptoms, joint pain or a swollen joint, or facial paralysis.

Can I Prevent Lyme Disease?

There's no surefire way to avoid getting Lyme disease. But you can minimize your risk. Be aware of ticks when you are in high-risk areas. If you work outdoors or spend time gardening, fishing, hunting, or camping, take precautions:

• Wear enclosed shoes or boots, long-sleeved shirts, and long pants. Tuck your pant legs into your shoes or boots to prevent ticks from crawling up your legs.
• Use an insect repellant containing 10% to 30% DEET (N,N-diethyl-meta-toluamide).
• Wear light-colored clothing to help you see ticks more easily.
• Keep long hair pulled back or wear a cap for protection.
• Don't sit on the ground outside.
• Check yourself for ticks regularly — both indoors and outdoors. Wash your clothes and hair after leaving tick-infested areas.

If you use an insect repellent containing DEET, always follow the recommendations on the product's label and don't overapply it. Place DEET on shirt collars and sleeves and pant cuffs, and only use it directly on exposed areas of skin. Be sure to wash it off when you go back indoors.

There is no vaccine for Lyme disease currently on the market in the United States.

How Is Lyme Disease Treated?

Lyme disease is usually treated with a 2- to 4-week course of antibiotics. 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 beginning treatment.

Is It Contagious?

Lyme disease is not contagious, so you can't catch it from another person. But you can get it more than once from ticks that live on deer, in the woods, or travel on your pets. So continue to practice caution even if you've already had Lyme disease.

What Can I Do to Feel Better?

You should know how to remove a tick just in case one lands on you or a friend. First, don't panic. Your risk of developing Lyme disease after being bitten by a tick is only about 1% to 3%. On top of that, it takes at least 24 to 48 hours for the tick to transmit the bacteria that causes Lyme disease. (To be safe, though, you'll want to remove the tick as soon as possible.) This is why a daily tick check is a good idea for people who live in high-risk areas.

If you find a tick:

• Call your doctor. He or she may want you to save the tick after removal so that the tick can later be identified as the type that may carry Lyme disease. You can put the tick in a jar of alcohol to kill it.
• Use tweezers to grasp the tick firmly at its head or mouth, next to your skin.
• Pull firmly and steadily on the tick until it lets go of the skin. If part of the tick stays in your skin, don't worry. It will eventually come out — although you should call your doctor if you notice any irritation in the area or symptoms of Lyme disease.
• Swab the bite site with alcohol.
  One note of caution: Don't use "folk remedies" like petroleum jelly or a lit match to kill and remove a tick.

Tick bites don't generally hurt — that's part of the difficulty in knowing whether someone has Lyme disease because pain usually helps to call attention to problems. So be on the lookout for ticks and rashes, and call your doctor if you're at all concerned.

Reviewed by: Stephen C. Eppes, MD
Date reviewed: August 2011