Lyme Disease

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What is Lyme disease?

Lyme disease is an infectious disease caused by the bacterium Borrelia burgdorferi, which is transmitted through tick bites. The infection resulting from these bites causes swelling, joint pain, rash, and flu-like symptoms. The disease can affect the nervous system, as well, causing headaches, dizziness, and other symptoms.

Lyme disease is spread by the deer tick (species Ixodes scapularis) in the northeastern United States and the western black-legged tick (species lxodes pacificus) in the Pacific Northwest. These ticks are typically found in wooded areas where deer are present. The tick carries the Borrelia burgdorferi bacterium, which it passes to humans when it bites them. Lyme disease occurs in approximately 30,000 people each year in the United States (Source: NIAID).

Lyme disease begins with the appearance of a red spot at the site of the tick bite within days to weeks following the bite. The spot may expand into a circular or oval-shaped rash and resemble a bull’s-eye: red in the center with alternating circles of white and red around it. This rash is known as erythema migrans and is unique to Lyme disease. Eventually, the rash will spread to different sites on the body. Additional symptoms include fever, aches, stiff neck, and other flu-like symptoms.

The symptoms of Lyme disease can be serious and may worsen without treatment. Untreated cases can lead to chronic arthritis (inflammation of the joints), swelling or inflammation of the nerve that controls facial muscles, and even paralysis. Seek prompt medical care if you experience rash, fever, muscle aches, headache, or other symptoms of Lyme disease after being bitten by a tick.


What are the symptoms of Lyme disease?

Symptoms of Lyme disease include rash, fever, aches and swelling. You may feel like you have the flu. Left untreated, symptoms can become more serious and include joint swelling and arthritis (inflammation of the joints), especially of the knees. Lyme disease can also affect the nervous system causing stiffness, headache, loss of muscle tone, and even paralysis.

Common symptoms of Lyme disease

Lyme disease causes symptoms that range in type and severity among individuals and may include:

  • Aches

  • Chills

  • Fatigue

  • Fever

  • Headache

  • Muscle pain

  • Neuropathy (Bell’s plasy, transverse myelitis)

  • Rash, starting with a bull’s-eye appearance that spreads over time

  • Stiff neck

  • Swelling of the knees and other large joints

  • Swollen lymph nodes

Symptoms that might indicate a serious condition

In some cases, Lyme disease can be a serious condition that should be immediately evaluated in an emergency setting. Because its symptoms can progress to serious conditions, it is important for you to be treated right away. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms including:

  • Abnormal pupil size or nonreactivity to light

  • Fever

  • Heart palpitations and dizziness due to changes in heartbeat

  • Loss of muscle tone on one or both sides of the face, possibly indicating paralysis

  • Pain that moves from joint to joint

  • Severe headaches and neck stiffness, possibly indicating meningitis (infection or inflammation of the sac around the brain and spinal cord)

  • Severe swelling in the knees or joints

  • Weakness or paralysis in the muscles of the face


What causes Lyme disease?

Lyme disease is an infectious disease caused by a tick bite. These ticks, the deer tick in the Northeast and the western black-legged tick in the Pacific Northwest, carry the bacterium Borrelia burgdorferi, which causes the disease. The bacterium usually lives in rodents and other small animals and is transmitted when a tick bites an infected animal and then bites a human.

Transmission to humans occurs most commonly in the summer when people are most likely to be outdoors and ticks are most active.

What are the risk factors for Lyme disease?

A number of factors increase the risk of developing Lyme disease. Not all people with risk factors will get Lyme disease. Risk factors for Lyme disease include:

  • Autoimmune disease (overactive immune response that causes the body to attack its own cells) or other conditions that compromise your immunity

  • Contact with animals, especially those that are prone to tick bites

  • Exposed skin unprotected by insect repellant and clothing

  • Extensive time spent outdoors, especially in the spring and summer

  • Extreme youth or advanced age

  • Hiking or camping in tick-infested areas

  • Pregnancy

Reducing your risk of Lyme disease

You may be able to lower your risk of Lyme disease by:

  • Applying insect repellant containing DEET if you will be outside

  • Avoiding areas of potential tick infestation

  • Inspect the body for ticks when changing clothes (adults and children)

  • Removing leaf debris, brush, and wood piles from your property

  • Wearing light-colored clothing (allowing ticks to be more easily spotted and removed)

  • Wearing long-sleeved shirts, tucked-in pants, and high boots if entering areas of possible infestation


How is Lyme disease treated?

If you suspect that you have Lyme disease, your health care provider will perform a series of tests, including drawing your blood to determine whether you have antibodies to the bacteria that cause Lyme disease. Not all of these blood tests are conclusive for Lyme disease, but your doctor will consider the test results together with your symptoms to make a diagnosis.

Lyme disease is treated with antibiotics. Recovery is usually rapid and complete, although some symptoms may recur or persist if the diagnosis is made at a later stage of the disease. It is important to follow your treatment plan for Lyme disease precisely and to take all of the antibiotics as instructed by your health care provider to avoid reinfection or recurrence.

Antibiotic medications used to treat Lyme disease

Antibiotic medications that are effective in the treatment of Lyme disease include:

  • Amoxicillin (Amoxcil)
  • Cefuroxime (Ceftin)
  • Doxycycline (Doryx)

What are the potential complications of Lyme disease?

Most cases of Lyme disease can be cured with antibiotics, especially if treatment is begun early in the course of illness. However, a small percentage of people with Lyme disease have symptoms that last for months to years after treatment with antibiotics.

Complications of Lyme disease range from joint pain and stiffness to meningitis (infection or inflammation of the sac around the brain and spinal cord) and paralysis. About 10% to 20% of untreated or complicated cases of Lyme disease can progress to arthritis.

You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of Lyme disease include:

  • Arthritis
  • Cognitive deficits (for example, memory loss and shorter attention span)
  • Fatigue
  • Meningitis (infection or inflammation of the sac around the brain and spinal cord)
  • Muscle and joint pain
  • Paralysis
  • Permanent vision loss
  • Sleep disturbances
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2019 Jan 5
  1. Lyme disease. National Institute of Allergy and Infectious Diseases.
  2. Lyme disease. Centers for Disease Control and Prevention.
  3. Bope ET, Kellerman RD (Eds.) Conn’s Current Therapy. Philadelphia: Saunders, 2013
  4. Tierney LM Jr., Saint S, Whooley MA (Eds.) Current Essentials of Medicine (4th ed.). New York: McGraw-Hill, 2011
  5. Stanek G, Wormser GP, Gray J, Strle F. Lyme borreliosis. Lancet 2012; 379:461
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