Lyme Disease: Symptoms, Causes, Treatment & Prevention

Lyme Disease is caused by borrelia burgdorferi bacteria transmitted by ticks. Learn about symptoms like rash, joint pain, neurological issues, and treatment options.

Lyme disease is caused by borrelia bacteria. It’s often spread through the bite of a tick.1 This illness is most common in certain parts of the United States, Europe, and parts of Canada.1 If you live or spend time in areas with lots of trees and grass, your risk is higher.1 You might notice a rash, joint pain, or other symptoms and should get treated quickly. Using tick repellent, covering up, and checking for ticks can lower your risk.

Key Takeaways

  • Lyme disease is a tick-borne illness caused by borrelia bacteria, primarily transmitted through the bite of infected deer ticks.
  • The disease is most prevalent in the upper Midwest, northeastern, and mid-Atlantic regions of the United States, as well as parts of Europe and Canada.
  • Lyme disease can cause a range of symptoms, including a distinctive rash, joint pain, and neurological issues, and requires prompt antibiotic treatment.
  • Preventive measures like using repellents, wearing protective clothing, and checking for ticks can help reduce the risk of contracting Lyme disease.
  • Prompt diagnosis and early treatment are crucial, as untreated Lyme disease can lead to more severe complications.

What is Lyme Disease?

Overview of Lyme Disease

Lyme disease is an illness caused by the borrelia bacteria.1 You can get it from a tick bite. This disease is found in areas like the upper Midwest and the northeastern U.S. It’s also common in parts of Europe and Canada.1

Borrelia Bacteria and Ticks

In North America, the black-legged tick, or deer tick, spreads Lyme disease.1 Europe has a similar disease caused by a different bacteria type. This type comes from castor bean ticks, sheep ticks, or deer ticks.1 Ticks get the bacteria from animals they bite, like deer or rodents, then pass it to us when they bite us.

Lyme Disease Symptoms

Lyme disease symptoms show up in stages. Some might not see the early signs.1

Early Localized Stage

A red bull’s-eye rash can appear at the tick bite site. This comes with flu-like feelings. You might have fever, headache, extreme tiredness, and muscle/joint pains.2

Rash and Flu-like Symptoms

About 70 to 80 percent of those infected get the red rash. It might not show up right away, appearing 3 to 30 days after the bite.2 Usually, it takes around 7 days to see the rash.2 It grows slowly and can get as big as 12 inches (30 cm) or more.2

Early Disseminated Stage

In this stage, more rashes might show up. You could have neck pain, lose the ability to move parts of your face, or have heart issues.2

Late Disseminated Stage

Without treatment, symptoms can get worse. This includes arthritis, often in the knees. You might also have pain, numbness, or weakness.2 In Europe, a rare skin condition could develop months or years later. It’s called acrodermatitis chronica atrophicans.

Lyme Disease Symptoms

When to See a Doctor

Most people with Lyme disease don’t recall being bitten by a tick3. It’s crucial to go to a doctor if you have symptoms like a bulls-eye rash or feel flu-like.3 Seeing a doctor early is key, as quick diagnosis and treatment can make a big difference.4 Even without remembering a tick bite, watch for symptoms if you’ve been in places with ticks.

Causes of Lyme Disease

Lyme disease comes from a bacterium called borrelia. Ticks, mainly the black-legged tick, spread this bacterium through their bites.1

These ticks pick up the bacteria by feeding on animals like deer or rodents. Then, they can give it to people when they bite and feed on our blood.1 Ticks of all ages can pass on Lyme disease.

Deer Ticks and Tick Bites

The black-legged tick, known as the deer tick, is key in spreading Lyme disease in North America.15 They live in wooded, shrubby, or grassy places, waiting to attach and feed on blood.15 If a tick stays on you a long time, you have more risk of getting Lyme disease.6

How Ticks Transmit Borrelia Bacteria

Ticks get the borrelia bacteria from animals they feed on, like deer or rodents.15 Then, they can pass this on to us if they bite and feed on our blood for several days.15 This can happen with both small (nymphal) and big ticks.1

Deer ticks

Risk Factors for Lyme Disease

Where you live or visit and your outdoor activities can affect your risk of Lyme disease. Deer ticks, carrying the bacteria, are common in upper Midwest, northeastern, and mid-Atlantic US. They are also found in south central and southeastern Canada.1 In Europe, the castor bean tick spreads the disease.1 Ticks like wooded, shrubby, or grassy areas. So, people hiking, camping, gardening, or working outside are at risk.1 Lyme disease can be caught during the spring, summer, and fall when ticks are most active. But, they can be active as long as it’s above freezing.1

Geographic Regions

Lyme disease is seen most in the upper Midwest, and northeastern and mid-Atlantic US.1 It’s also a problem in Europe and south central and southeastern Canada.1 In Europe, a different species causes the disease than North America.1

Outdoor Activities and Seasons

Outdoor passions like hiking or gardening put you at risk. Ticks love wooded, shrubby, or grassy spots.1 The risk is highest when ticks are most active, in spring, summer, and fall. But remember, ticks can be out when it’s above freezing.1

Complications of Untreated Lyme Disease

Leaving Lyme disease untreated can cause serious problems. For instance, arthritis can be a big issue, especially in the knees. It might stick around for a long time or show up on and off.7

In Europe, you might get a skin issue called acrodermatitis chronica atrophicans. It makes your skin discolored and puffy on the hands, feet, and joints.1

Even after you’re treated, symptoms like joint pain, tiredness, and memory problems could stay. This is called post-treatment Lyme disease syndrome. What exactly causes it isn’t clear. But not finishing treatment, getting infected again, or an automatic immune response might play a part.

Roughly 60% of those not treated will face arthritis attacks later on. This happens in the late stage of Lyme disease.7

Untreated Lyme disease can lead to severe issues like chronic arthritis, heart inflammation, and nerve problems.8 In the U.S., big joint arthritis, especially in the knees, is common in the third stage.1

After Lyme disease treatment, some might still have symptoms. These could include arthritis, body aches, always feeling tired, and issues remembering. This is post-treatment Lyme disease syndrome. The reasons for this aren’t crystal clear. But skipping some of your treatment, getting infected again, or an immune response might be involved.

Preventing Lyme Disease

The best way to avoid Lyme disease is by not getting bitten by ticks.9 They live in places like woods or grassy areas.9 Tick bites happen a lot more in the summer.

Using Tick Repellents

It’s smart to use insect repellents with DEET, picaridin, or lemon eucalyptus.9 These are good for keeping ticks away.9

Protective Clothing

Wear long sleeves, long pants, and light clothes when outside.9 Ticks are easy to see on light colors.9

Checking for Ticks

After being outside, check for ticks on yourself, gear, and pets.9 It’s important to remove ticks quickly to prevent disease.9 Most people with Lyme disease get a rash, but not always the bull’s-eye kind.9

Additional Prevention Tips

Stay on cleared paths, use high heat to dry clothes, and check outdoor pets for ticks.9 Doing these things lowers the chance of getting tick bites and Lyme disease.

Diagnosing Lyme Disease

Diagnosing Lyme Disease is tough because its symptoms are similar to other illnesses. Doctors begin by discussing your medical history and giving you a physical exam. They look for signs like the bull’s-eye rash. Blood tests can show if you have antibodies for the bacteria causing Lyme disease. But, these results might not be clear at first or could be missing in some cases.10

When symptoms and possible exposure to ticks make doctors suspect Lyme Disease, they might start treatment before labs confirm it.3 It’s key to treat it early for a better chance of recovery.

Lyme Disease Diagnostic TestsDescription
ELISA TestUsed to diagnose Lyme disease, a positive result must be confirmed with a Western blot test.10
Western Blot TestConfirms a positive ELISA test result for a Lyme disease diagnosis.10
AntibioticsMay be needed for up to a month to treat Lyme disease.10
Blood SampleRequired for Lyme disease tests to check for disease-fighting antibodies.10

Getting tested for Lyme Disease helps, but doctors also use your history, exam, and sometimes gut feelings.3 Starting treatment soon is crucial for the best results.

Treatment of Lyme Disease

Lyme disease gets treated with antibiotics, which work well in most cases.3 Common antibiotics like doxycycline, amoxicillin, or cefuroxime are used early on, often for 2-4 weeks.3 For severe cases affecting the heart, nervous system, or causing lasting arthritis, doctors may prescribe IV antibiotics.3 Early and proper antibiotic treatment usually leads to full recovery with no long-term issues.11

Antibiotics for Lyme Disease

Antibiotics stop Lyme disease from getting worse and can reduce how bad symptoms are.11 For more severe forms, IV therapy is common. It can last from 10 to 28 days, but usually 14.11 In \most cases of late Lyme disease with arthritis, oral antibiotics for 28 days help. IV antibiotics might be needed if oral treatment doesn’t work.11 Neurologic conditions from late Lyme disease require IV antibiotics. Ceftriaxone or cefotaxime are common, given daily for two to four weeks.11

However, a small number of patients may still have symptoms after treatment, known as post-treatment Lyme disease syndrome.11 Studies show that using more antibiotics doesn’t help these ongoing symptoms.3

Post-Treatment Lyme Disease Syndrome

Some people with Lyme disease still feel sick after taking antibiotics. They have joint/muscle pain, feel tired, and have trouble remembering things.12 Doctors call this condition post-treatment Lyme disease syndrome (PTLDS). Its exact cause isn’t clear, but it might be linked to how the immune system reacts, not fully ending the infection, getting infected again, or the presence of bacteria bits.12

About 476,000 Americans get Lyme disease each year, the CDC says, and 10% to 20% of them may develop PTLDS.12 The NIAID has started funding studies with around $3.2 million to learn more about PTLDS.12 They’ve given five research teams money to look into why some people keep feeling sick.12 This study will last for five years and include scientists from various universities.12

Doctors sometimes use long antibiotic treatments to try to help with PTLDS. But, studies have shown that this might not work for everyone.12 Right now, there’s no one agreed-upon way to treat PTLDS. Doctors find it hard to diagnose because its symptoms are many and there’s no clear proof of an ongoing infection.12

Around 100,142 people might keep feeling sick after Lyme treatment, a study shows.13 Some have had bad reactions to antibiotics or IV treatments, with 1,568-1,574 cases noted.13 Others have gotten seriously sick from bacteria during their ‘chronic Lyme disease’ treatment in the US, around 607-609 cases.13 A rare reaction to Ceftriaxone, antibiotic, called immune hemolytic anemia, has been seen in 133-137 cases.13

While we still need more research, the work being done to understand and treat PTLDS is very important.12 It’s vital for improving how people with this syndrome feel and their long-term health.12

Lyme Disease in Pets

Lyme disease can affect pets, especially dogs who are outdoor lovers.14 It’s caused by a bacteria called Borrelia burgdorferi, carried by infected ticks.14 These ticks, mainly deer ticks, live in the east U.S., Midwest, and Canada, including Ontario.15 Pets, like people, get Lyme disease from tick bites. They might show signs like limping, fever, not eating, and feeling tired.14 It usually takes a few months after infection for these symptoms to show.

About 5-10% of pets with Lyme disease will look sick.15 And some might get very sick, affecting their kidneys.15 The tick that spreads Lyme disease needs to be on its host for a day or two to pass the bacteria.15 They’re most active from early spring through fall.

To confirm Lyme disease in pets, doctors do an antibody test not sooner than four weeks after a tick bite.14 Treating Lyme disease in pets involves using antibiotics for about four weeks.14 A vaccine is available for pets, especially those in high-risk areas. They need two doses close together at first.

Antibodies from the infection can show up in testing after 3-4 weeks.16 If an animal is infected, their antibody levels might go down after 6-8 weeks, especially with early treatment.16 Testing again might be needed, 3 or 6-8 weeks after treatment, to check on the infection.16 Antibiotics can help pets feel better, but they might not change the antibody levels.

Vaccinated pets can still get Lyme disease, especially in high-risk areas.16 But catching and treating it early can be really helpful.16 It’s important to check their vaccination each year. This makes sure they have enough protection.16 The Lyme Multiplex test can show if the vaccine is working to produce the needed antibodies.

Preventing Lyme is all about avoiding ticks, using tick repellents, and vaccinating when needed.14 Ticks should be removed gently and completely to avoid spreading Lyme disease.

Outlook and Recovery

Doctors can usually diagnose Lyme disease quickly. When treated promptly with the right antibiotics, most people fully recover. Kids respond well to a 2-4 week antibiotic plan. About 75% of them are back to normal within six months after the end of treatment.17 Notably, 31% of these kids get better within a month; for 30%, it’s in one to three months. For 14%, it takes four to six months.17

But sometimes, a few patients still feel unwell after treatment. This ongoing condition is called post-treatment Lyme disease syndrome (PTLDS). In kids, about 22% have symptoms for six months or more.17 From this group, 9% seem to have PTLDS.17 For these cases, the long-term effects are not clear. We need more studies to fully get what’s happening.

Overall, Lyme disease often gets better fully if found and treated early. However, some kids might not be fully healed at the time of study. Only 1% felt symptoms that really affected their daily life.17 Among those diagnosed in the US yearly, kids between 5 and 9 years make up a big part.17 So, protecting from tick bites is key to lowering the risk of Lyme disease.


Lyme disease is a severe, yet curable18 illness spread by ticks. It’s caused by the borrelia bacteria. The sickness shows in many ways, from a clear rash to pain in the joints and mind.

Quickly spotting it and using the right drugs is vital. Early care stops bigger problems. Though most heal fully, a few might still feel sick.18

Ways to avoid it include wearing bug spray, covering up, and checking for ticks. This is more important in places where Lyme disease is common.18 Learning about how the disease starts, its signs, and how to prevent it helps keep you safe.

Lyme disease is on the rise, and it’s tough to catch and treat.19 This shows how we need to be very careful and informed. More learning and talking about it will hopefully make things better for those who get it.


What is Lyme disease?

Lyme disease is caused by a bacteria transmitted by tick bites. It affects humans.

What are the main symptoms of Lyme disease?

Early symptoms include a bull’s-eye rash and flu-like signs. These signs can be fever, headache, tiredness, and muscle or joint pain. Later, it can lead to more rashes, arthritis, and problems with the nervous system.

How is Lyme disease diagnosed and treated?

Doctors use physical exams, your medical history, and blood tests for diagnosis. Treatment involves antibiotics. The specific type and duration of antibiotics depend on how bad the disease is.

What are the risk factors for getting Lyme disease?

If you’re often in areas with ticks, especially from spring to fall, you have a higher risk. This includes places with a lot of woods, grass, or bushes.

How can Lyme disease be prevented?

To prevent Lyme disease, use tick repellent and wear protective clothes. After being outside, check for ticks. If you find one, remove it quickly.

What are the potential complications of untreated Lyme disease?

Untreated Lyme disease can lead to more severe conditions. These include arthritis, issues with the nervous system, and a specific skin problem.

Can Lyme disease affect pets?

Absolutely, Lyme disease can affect pets, especially dogs. Vets use similar methods to humans to diagnose and treat it in pets.

What is post-treatment Lyme disease syndrome?

Some patients feel sick even after their treatment ends. They might still have pain, feel tired, and have problems remembering things. This is called post-treatment Lyme disease syndrome. Doctors are not sure why it happens.

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