What Is Lyme Disease?

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Lyme disease is a condition caused by bacteria transferred to humans via tick bites. It is a complex disease that causes symptoms across many parts of the body and can last from weeks to years. It can be a serious illness, but fortunately, effective medications exist to treat Lyme disease and there are many steps you can take to prevent it.

If you live somewhere with a high incidence of Lyme disease and develop symptoms of infection, it is important you reach out to your healthcare provider. It is not uncommon for people to be bit and never know it until they begin showing signs of Lyme disease. Your provider may be able to run tests to determine if you need to begin treatment for Lyme disease. Doing this can prevent complications down the road.

Lyme Disease Symptoms

When left untreated, Lyme disease typically unfolds in three stages: early localized, early disseminated, and late Lyme disease.

Early Localized Stage

The early localized stage generally occurs 3-30 days after the tick bite and is characterized by a low-grade fever, aches, swollen lymph nodes, and the appearance of erythema migrans (EM). EM is a rash that begins at the site of the tick bite and spreads outwards. It can reach 12 inches across or more and often partially clears as it expands, creating the well-known "bull's eye" appearance. This rash appears in 70-80% of people with Lyme disease and appears about 7 days after the bite.

It's important to note that tick saliva can cause a rash that is different from EM. If you remove a tick and notice a rash the size of a dime that doesn't spread or that persists only just after the tick is removed, it is likely not EM.

Early Disseminated Stage

The early disseminated stage begins days to months after the start of the infection. These symptoms can last 3-5 months but generally do not return after that. Symptoms can include:

  • Fever
  • Malaise
  • Dizziness
  • Headache
  • Muscle and joint pain
  • Chest pain
  • Heart palpitations
  • Feeling short of breath
  • Double vision
  • Encephalopathy (a term for any disease process that affects brain structure or function)
  • Meningitis
  • Facial palsy (one or both sides of the face losing muscle tone and drooping)

Lyme disease bacteria can infect the heart and cause a condition called Lyme carditis. This condition can cause a dangerous heart rhythm that can be fatal. However, with the right treatment, people usually recover from Lyme carditis in 1-6 weeks.

Late Lyme Disease Stage

The late stage of Lyme disease usually occurs within a year of infection but can occur multiple years after. One key feature of late Lyme disease is arthritis affecting the knee, but it can cause arthritis in other areas too. Neurological symptoms such as meningitis, cognitive deficits, and facial palsy are also found in this stage.


Lyme disease is caused by the bacterium Borrelia burgdorferi and sometimes Borrelia mayonii. Some black-legged ticks—which are commonly called deer ticks—carry these bacteria and can transmit it to humans through their bite. Lyme disease has been reported all over the country but is especially common in Minnesota, Wisconsin, and the Northeastern United States. Cases are most commonly reported from late spring to early fall.

The bacteria begins to spread around the area of the bite, causing EM. As the bacteria spread to different parts of the body, symptoms of infection may begin to show there. The bacterium Borrelia burgdorferi has a tendency to affect joints, although it is not well understood why.

Risk factors for developing Lyme disease include:

  • Walking or hiking in woods, high grass, or bushes
  • Working outside
  • Living in a place with high incidences of Lyme disease
  • Being female

Not every tick bite results in Lyme disease. A tick needs to be attached to your skin for a while before it can transmit the infection. However, if something puts you at risk of being bit by a tick, it could also put you at risk of developing Lyme disease.


When determining if you may have Lyme disease, your healthcare provider will likely first ask you a series of questions. They will want to know what symptoms you have, if you have been in environments where you were exposed to infected blacklegged ticks, and if you may have any conditions that could produce similar symptoms to Lyme disease.

If you have classic signs and symptoms of Lyme disease, such as EM, and have a known tick exposure, your provider may begin treatment without looking at any bloodwork. However, many symptoms of Lyme disease can be vague (such as fever or fatigue), or you may not remember being bitten by a tick, so often providers will send out lab tests to confirm infection.

The majority of blood tests for Lyme disease test for the presence of antibodies, which are proteins created by your body to fight infection. These antibodies may not show up on tests for several weeks after the infection begins; therefore, there is a possibility of falsely testing negative if you get bloodwork done too soon. A false positive test may occur if you have certain other infectious or autoimmune illnesses.

Treatments for Lyme Disease

Since Lyme disease is caused by a bacterial infection, antibiotics are the main course of treatment. The type of antibiotics, dose, and whether it is given orally or intravenously (through an IV) will depend on different factors such as your age and where symptoms are occurring.

Some of the antibiotics frequently used to treat Lyme disease include:

  • Doxycycline
  • Amoxicillin
  • Cefuroxime
  • Ceftriaxone

Depending on your symptoms, you may need treatments in addition to antibiotics. For example, those with Lyme carditis may need a temporary pacemaker to manage dangerous heart rhythms while the infection is treated.

How to Prevent Lyme Disease

You cannot get Lyme disease if you aren't bitten by an infected tick, so preventing tick bites is an important step in preventing infection. A few steps for keeping yourself safe from ticks include:

  • Use a bug repellent shown to work against ticks, such as picaridin. Some of these repellents have powerful chemicals in them, so be sure to read the instructions to make sure you are using them safely.
  • Wear long sleeves and tuck your pants into your socks and boots when hiking outside, as it reduces the amount of skin a tick has access to. Wearing light-colored clothes can help make ticks more visible.
  • Stay on trails when walking around outside and avoid tall grasses, leaf piles, or bushes.
  • If you have pets, ask your veterinarian about tick control options.

If a blacklegged tick bites you, it takes at least 36-48 hours of the tick feeding before it transmits the bacterium that causes Lyme disease. For this reason, thoroughly checking your skin for ticks after spending time outdoors and removing any you find can go a long way toward preventing Lyme disease.

When removing a tick, grasp it with tweezers as close to your skin as possible and tug firmly but gently, you don't want the tick to burst as that can spread the bacteria. Wash your hands well after.


If you have symptoms of pain, difficulty thinking or concentrating, or fatigue that last more than six months after treatment you may have a complication of Lyme disease called post-treatment Lyme disease syndrome (PTLDS). More research is needed to understand why PTLDS occurs and why some develop it and some do not.

Some scientists believe PTLDS is an autoimmune response triggered in the body by the original Lyme disease. Others believe the symptoms of PTLDS are from other causes not related to Lyme disease at all. If you believe you may have PTLDS, it is important to reach out to your healthcare provider to determine the next steps.


The outlook for most people with Lyme disease is promising. The vast majority of individuals recover after treatment with antibiotics. Depending on the severity of the disease, treatment can last days to weeks. Getting diagnosed and treated early on in the infection can prevent the disease from progressing.

Those with PTLDS may continue to experience symptoms months after treatment. While there is no cure for PTLDS, your healthcare provider can work with you to manage symptoms. Most of these symptoms will gradually go away over time.

Frequently Asked Questions

  • Is Lyme disease contagious?

    No, there is no evidence that Lyme disease can be transmitted between two humans.

  • Does Lyme disease stay with you for life?

    No, Lyme disease is treatable with antibiotics and the majority of people recover completely and quickly. Some may have lingering symptoms from the damage the disease inflicts on the body or develop PTLDS. However, these are not the same thing as having a lingering active infection.

  • Could I have had Lyme disease and not know it?

    Yes, it is possible. Many people do not know they've been bitten by a tick until they show signs of Lyme disease. Approximately 1.6%-7% of infected individuals may have no symptoms. If you have no symptoms and don't know you've been bitten, it is possible you could have Lyme disease and not know it.

  • How long after a tick bite will you test positive for Lyme?

    You may test positive for as long as months to even years after you have recovered. The blood test for Lyme disease looks for specific antibodies, which your body continues to produce long after you are no longer infected.

  • What happens if Lyme disease goes untreated for years?

    Early treatment can prevent the disease from progressing to the late stage. Untreated Lyme disease that progresses to this stage can lead to serious issues with your joints and nervous system.

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18 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Signs and symptoms of untreated Lyme disease.

  2. Hu L. Patient education: What to do after a tick bite to prevent Lyme disease (Beyond the basics). In: Steere AC, Hall KK, eds. UpToDate. UpToDate; 2023.

  3. Skar GL, Simonsen KA. Lyme disease. In: StatPearls. StatPearls Publishing; 2023.

  4. Centers for Disease Control and Prevention. Lyme carditis.

  5. Centers for Disease Control and Prevention. Lyme disease.

  6. Centers for Disease Control and Prevention. Lyme disease map.

  7. The National Institute for Occupational Safety and Health. Lyme disease.

  8. Centers for Disease Control and Prevention. Diagnosis and testing.

  9. Centers for Disease Control and Prevention. Lyme arthritis.

  10. Mass.gov. Lyme disease.

  11. Centers for Disease Control and Prevention. Post-treatment Lyme disease syndrome.

  12. Hu L. Patient education: Lyme disease treatment (Beyond the basics). In: Steere AC, Hall KK, eds. UpToDate. UpToDate; 2023.

  13. Centers for Disease Control and Prevention. Treatment of Lyme disease.

  14. Ścieszka J, Dąbek J, Cieślik P. Post-Lyme disease syndrome. Reumatologia. 2015;53(1):46-48. doi:10.5114/reum.2015.50557

  15. Centers for Disease Control and Prevention. Lyme disease: What you need to know.

  16. Centers for Disease Control and Prevention. Lyme disease frequently asked questions.

  17. Centers for Disease Control and Prevention. Transmission.

  18. Hatchette T, Davis I, Johnston B. Lyme disease: Clinical diagnosis and treatmentCan Comm Dis Report. 2014;40(11):194-208. doi:10.14745/ccdr.v40i11a01

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