Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

Definition

Lyme disease is a bacterial infection. The infection is spread from the bite of an infected deer tick.

Causes

Lyme disease is caused by bacteria found in some deer ticks. An infected tick passes Lyme disease to humans through its bite.

If untreated, the bacteria can pass into the blood. The blood will carry it through the body. The bacteria may then settle in various body tissues. The spread of the infection can cause a number of symptoms, ranging from mild to severe.

Risk Factors

Factors that increase your risk of Lyme disease include:

  • Living in the northeastern, northwestern, mid-Atlantic, or upper north-central regions of the United States and northwestern California
    • Peak tick season in the northeast is April through September
  • Outdoor activities, such as hiking, camping, and gardening in areas/seasons with deer ticks
  • Living near or going to wooded, grassy areas
  • Working outdoors such as surveying, landscaping, forestry, gardening, and utility company service work

Symptoms

The symptoms of Lyme disease will be different in each person. They can also range from mild to severe.

The first sign may be a red rash. The rash starts as a small red spot at the site of the tick bite. It will then spread over the next few days or weeks to form a circular or oval-shaped rash. Sometimes the rash resembles a bull's eye with a red ring around a clear area with a red center. The rash may cover a small dime-sized area or a wide area of the body.

Lyme Disease Rash

This is an example of a Lyme disease rash shaped like a bull's eye. It may not always be this shape, nor will a rash always appear.
Copyright © Nucleus Medical Media, Inc.

In the first 3-30 days after the bite, if the infection has not spread you may notice:

  • Rash
  • Muscle and joint aches
  • Headache
  • Fever
  • Fatigue
  • Swollen glands

These symptoms do not necessarily mean you have Lyme disease, even if you have spent time outdoors. See your doctor right away if you have these symptoms and think you have been exposed to a tick.

An infection that has begun to spread may cause the following symptoms in days to weeks after the bite:

Symptoms can develop in months or years after the tick bite in untreated infections. These symptoms may occur regularly or intermittently and include:

Less common symptoms of late Lyme disease include:

  • Heart abnormalities
  • Eye problems, such as conjunctivitis
  • Chronic skin disorders
  • Limb weakness
  • Persistent motor coordination problems

Diagnosis

A doctor may be able to diagnose Lyme disease based on your symptoms and the history of a tick bite.

After four weeks of Lyme disease, your body may create antibodies against the infection. Your doctor may look for these antibodies with a blood test. The blood test cannot confirm or rule out Lyme disease. Instead, the results of the blood test will be used in combination with your symptoms and personal history to make a diagnosis.

Treatment

Lyme disease responds well to antibiotics. These medications can kill bacteria. Antibiotics used most often include:

  • Doxycycline—cannot be used in women who are pregnant or children under 8 years of age
  • Amoxicillin—can be used in women who are pregnant or children under 8 years of age
  • Cefuroxime

The length of your antibiotic treatment will depend on your condition. You may need to take them for 10 days to 3 weeks or more. You may be given the antibiotics by mouth or by injection.

To relieve pain from chronic arthritis you doctor may recommend:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
    • Ibuprofen (Advil, Genpril, Medipren, Motrin, Nuprin, Rufen)
    • Naproxen sodium (Aleve, Anaprox, Naprosyn)
  • Steroid injection directly into the joint

Prevention

Try the following to help prevent Lyme disease:

If you live or are visiting northeastern, northwestern, mid-Atlantic, or upper north-central regions of the United States and northwestern California:

  • Avoid areas that are likely to be infested with deer ticks such as moist, shaded, wooded, or grassy areas
  • When going to wooded, grassy areas, especially in spring and summer:
    • Wear light-colored clothing with a tight weave to spot ticks easily.
    • Wear enclosed shoes.
    • Wear a long sleeve shirt. Tuck it into your pants.
    • Tuck pants into socks or boot tops.
    • Wear a hat.
  • Stay on cleared, well-traveled paths and walk in the center of trails to avoid overgrown grass and brush. Avoid sitting on the ground or stone walls.
  • Remove leaf litter, brush, and woodpiles from around the home and the edges of the yard.

Insect repellent can help prevent tick bites. Repellents containing DEET can be applied to clothes and exposed skin. Repellents that have permethrin can be applied to pants, socks, and shoes, but not to skin. Repellents can cause eye irritation and skin reactions. Be sure to read the label for instructions on application, including:

  • Do not apply near eyes, nose, or mouth.
  • Do not apply to children's hands.
  • Wash your skin when you return indoors.

Deer ticks are unlikely to pass the infection unless they are in contact with the skin for at least 24 hours. After spending time outdoors in risk area:

  • Do a full-body check for ticks at the end of a day spent outdoors. Consider bathing or showering within 2 hours of coming indoors.
  • Check your child for ticks. Make sure to check for hidden areas like the hair, around the ears, or behind the knees.
  • Check pets and gear for ticks.
  • Put clothes worn outdoors in the dryer for 20 minutes. This will kill any unseen ticks.

If you do find a tick, remove it by doing the following:

  • Use a pair of tweezers to grasp the tick by the head, as close to the skin as possible.
  • Pull directly outward. Use gentle but firm forces. Do not twist the tick out. Try not to crush the tick's body or handle it with bare fingers. This can spread the infection.
  • Wipe the site with an antiseptic to prevent infection.

There are some steps that do not help. They may cause more problems.

  • Do not put a hot match to the tick.
  • Do not cover the tick with petroleum jelly, nail polish, or any other substances.

If you have been bitten by a deer tick, especially if you live in an area where Lyme disease is common, you should watch for a rash to appear. It may take about one month after the bite for the rash to show.

If you have a tick bite and live in a high-risk area, your doctor may recommend a dose of the antibiotic doxycycline. This may reduce the risk of contracting Lyme disease if taken within 72 hours after a tick bite. However, this antibiotic can have serious side effects in children less than 8 years old. This prevention step is only used in people older than 8 years.

The risk of catching Lyme disease after a single tick bite is low. Many experts do not recommend preventive antibiotic treatment.