Lyme disease is an infection spread by tick bites

Lyme disease is an infection caused by bacteria called Borrelia burgdorferi. You get it when an infected tick bites you and stays attached long enough to pass the bacteria into your bloodstream. Not all ticks carry the bacteria, and not every tick bite leads to infection — but the risk is real in areas where infected ticks live.

The infection can affect your joints, heart, nervous system, and skin. Some people recover fully with treatment. Others have symptoms that last months or years, even after antibiotics. The key to better outcomes is catching it early, which means knowing what to look for after a tick bite.

Key Takeaways

  • Lyme disease spreads through tick bites and is caused by bacteria that enter your bloodstream when an infected tick stays attached for several hours.
  • The first sign is often a rash that looks like a bull's-eye, appearing days to weeks after the bite, though not everyone gets a rash.
  • Early symptoms include fever, chills, fatigue, and body aches that resemble the flu.
  • Doctors diagnose Lyme disease using blood tests, but these tests work better weeks after infection starts, so early diagnosis often relies on the rash and your history of tick exposure.
  • Antibiotics taken early can prevent the infection from spreading to joints, the heart, and the nervous system.

How the infection spreads and who is at risk

Lyme disease spreads only through tick bites — you cannot catch it from another person, from animals, or through food or water. The ticks that carry the bacteria are small, often the size of a poppy seed, which is why people often do not notice them. The tick must stay attached for several hours (usually at least 24 hours) to transmit the bacteria, so prompt removal lowers your risk.

You are at higher risk if you spend time in wooded areas, tall grass, or brush where ticks live. This includes hiking, camping, gardening, or working outdoors. Ticks are most active from spring through fall, though they can bite year-round in warmer climates. The infection occurs across North America, Europe, and parts of Asia, but is most common in the northeastern and upper midwestern United States.

The rash and early warning signs

The most recognizable sign of Lyme disease is a rash called erythema migrans. It often appears 3 to 30 days after the tick bite and looks like a red circle with a clear center — the "bull's-eye" pattern. The rash can be warm to the touch and may itch or burn, but it is usually not painful. It often starts at the bite site and spreads outward, sometimes reaching several inches across.

Not everyone gets this rash, so do not assume you are safe if your skin looks normal. Early symptoms that appear alongside or instead of the rash include fever, chills, fatigue, body aches, and headache — much like the flu. Some people also have joint pain or swelling. These symptoms can come and go, and they may be mild enough that you do not seek medical care right away.

What happens if Lyme disease is not treated early

If the infection spreads beyond the skin, it can reach your joints, nervous system, and heart. Lyme arthritis causes swelling and pain, usually in the knees, though other joints can be affected. This can develop weeks to months after infection and may become chronic.

Lyme neuroborreliosis affects the nervous system and can cause facial paralysis (Bell's palsy), numbness, tingling, or meningitis-like symptoms such as stiff neck and severe headache. Lyme carditis affects the heart's electrical system and can cause irregular heartbeat or chest pain. These complications are less common than joint problems, but they are serious and require prompt treatment.

Some people report ongoing symptoms months or years after treatment — fatigue, joint pain, or difficulty concentrating. This is sometimes called post-treatment Lyme disease syndrome, though doctors still debate its cause and how common it truly is. Early treatment with antibiotics significantly reduces the risk of these complications.

How doctors test for Lyme disease

Doctors diagnose Lyme disease using a combination of your symptoms, your history of tick exposure, and blood tests. The most common test is called an ELISA (enzyme-linked immunosorbent assay), which looks for antibodies your immune system makes in response to the infection. If the ELISA is positive, doctors usually order a second test called a Western blot to confirm the diagnosis.

Blood tests work best weeks after infection starts, because your body needs time to produce enough antibodies to detect. This means early diagnosis — when you have the rash and early symptoms — often relies on what you tell your doctor rather than on test results. If you remember a tick bite or have the bull's-eye rash, your doctor may start antibiotics before the blood tests come back, because waiting for results can delay treatment.

A test called a PCR (polymerase chain reaction) can detect the bacteria's DNA directly, but it is less commonly used and is not always available. Your doctor will choose the right test based on how long you have had symptoms and what your symptoms are.

Treatment with antibiotics

Lyme disease is treated with antibiotics, and the type depends on how far the infection has spread and how long you have had it. For early-stage infection with a rash and no signs of spread, doctors typically prescribe doxycycline (for adults and children over 8 years old) or amoxicillin (for younger children and pregnant women) taken by mouth for 14 to 21 days.

If the infection has spread to the nervous system or heart, you may need intravenous antibiotics such as ceftriaxone, given through a vein in the hospital or at an outpatient clinic. Treatment for late-stage Lyme arthritis usually involves oral antibiotics for 28 days. Starting antibiotics early — ideally within the first few weeks — gives you the best chance of full recovery and prevents complications.

Some people have side effects from antibiotics, such as nausea, diarrhea, or yeast infections. Tell your doctor about any reactions so they can adjust your treatment if needed. Finishing the full course of antibiotics, even if you feel better, is important to clear the infection completely.

Prevention and what to do after a tick bite

The best way to prevent Lyme disease is to avoid tick bites. When you are in areas where ticks live, wear long sleeves and pants, tuck your pants into your socks, and use an insect repellent containing DEET on your skin and permethrin on your clothing. Check your body for ticks after being outdoors, paying special attention to warm, moist areas such as the groin, armpits, and behind the knees.

If you find a tick, remove it promptly by grasping it with tweezers as close to your skin as possible and pulling straight out. Do not twist, crush, or squeeze the tick, because this can push bacteria into your skin. Clean the bite area with soap and water or rubbing alcohol. Save the tick in a sealed bag or container if you can — some areas have tick-testing programs that can tell you whether it carried Lyme disease bacteria.

Watch for a rash or flu-like symptoms over the next few weeks. If you develop a bull's-eye rash or fever after a known tick bite, contact your doctor right away. Early treatment makes a significant difference in preventing complications.

Frequently Asked Questions

Can you get Lyme disease from a tick that is not attached to your skin?

No. The tick must be attached and feeding for several hours to transmit the bacteria. A tick crawling on your skin or one you brush off immediately poses no risk. This is why prompt removal is so important — the longer the tick stays attached, the higher your risk.

What should I do if I cannot remember whether I had a tick bite?

Tell your doctor about any outdoor activities in the weeks before your symptoms started, especially in wooded or grassy areas. You may not remember a small tick bite, but your doctor can still test for Lyme disease based on your symptoms and the time of year. A rash or flu-like illness in spring or summer in a high-risk area is reason enough to seek testing.

Does Lyme disease go away on its own without treatment?

Some people's immune systems may clear a mild infection, but this is not reliable. Without antibiotics, the bacteria can spread to joints, the nervous system, and the heart, causing serious complications. Antibiotics are the standard treatment and significantly improve outcomes, so do not wait to see if symptoms resolve on their own.

Can you get Lyme disease twice?

Yes, you can be infected more than once. Having Lyme disease does not make you immune. If you live or spend time in an area where infected ticks are common, you remain at risk with each tick bite. Continue using prevention measures even if you have been treated before.

Is there a vaccine for Lyme disease?

A vaccine called LYMErix was available in the United States in the late 1990s but was withdrawn from the market due to low demand. Currently, no Lyme disease vaccine is available in the United States, though research into new vaccines is ongoing. Prevention through tick avoidance and prompt removal remains the best strategy.