What is Lyme disease?
Lyme disease is a bacterial infection spread by ticks. You can get Lyme disease if you're bitten by an infected tick. But most people who've had a tick bite don't get Lyme disease. If you don't treat Lyme disease, it can lead to problems with your skin, joints, heart, and nervous system.
What causes it?
Lyme disease is caused by a bacteria. Infected ticks spread the bacteria by biting people or animals.
Two types of ticks carry the Lyme disease bacteria in the U.S. They are:
- Deer ticks. They spread the disease in the Northeast and Midwest.
- Western black-legged ticks. They spread the disease along the Pacific coast, mostly in northern California and Oregon.
Dogs, cats, and horses can become infected with Lyme disease bacteria, but they can't pass the illness to humans. But infected ticks may fall off the animals and then bite and infect humans.
Can you prevent it?
To help prevent Lyme disease, cover up as much skin as you can when you will be in wooded or grassy areas. Wear a hat, a long-sleeved shirt, and long pants with the legs tucked into your socks. Use a bug repellent with DEET that can keep away ticks.
What are the symptoms?
One sign of Lyme disease is a round, red rash that spreads at the site of a tick bite. This rash can get very large. Flu-like symptoms are also common. If Lyme disease goes untreated, you can develop swelling and pain in your joints, plus problems with your heart and nervous system.
How is it diagnosed?
Your doctor will ask questions about your symptoms and do a physical exam. The round, red rash is a sign of Lyme disease. Your doctor will also ask questions to find out if you've been around infected ticks. You may have a blood test to see if you have certain antibodies in your blood.
How is Lyme disease treated?
Lyme disease is treated with antibiotics. If Lyme disease goes untreated, it can lead to problems with your skin, joints, nervous system, and heart. The problems often get better with antibiotics. But in rare cases, they can be lifelong.
- Avoid ticks.
- Learn where ticks are found in your community. Stay away from those areas if possible.
- Cover as much of your body as possible when you work or play in grassy or wooded areas. Wear a hat, a long-sleeved shirt, and long pants with the legs tucked into your socks. And keep in mind that it's easier to see ticks on light-colored clothes.
- Use insect repellents, such as products containing DEET. You can spray them on your skin.
- Use products that contain 0.5% permethrin on your clothing and outdoor gear, such as your tent. You can also buy clothing already treated with permethrin.
- Take steps to control ticks on your property if you live in an area where Lyme disease occurs. Clear leaves, brush, tall grasses, woodpiles, and stone fences from around your house and the edges of your yard or garden. This may help get rid of ticks.
- When you come in from outdoors, check your body for ticks, including your groin, head, and underarms. The ticks may be about the size of a poppy seed. If no one else can help you check for ticks on your scalp, comb your hair with a fine-tooth comb.
- If you find a tick, remove it quickly. If you can't remove it with your fingers, use tweezers to grasp the tick as close to its mouth (the part in your skin) as possible. Slowly pull the tick straight out—do not twist or yank—until its mouth releases from your skin. If part of the tick stays in the skin, leave it alone. It will likely come out on its own in a few days.
- Check your clothing, outdoor gear, and pets. Ticks can come into your house on them. The ticks can then fall off and attach to you.
- Check your clothing and outdoor gear. Remove any ticks you find. Then put your clothing in a clothes dryer on high heat for about 4 minutes to kill any ticks that might remain.
- Check your pets for ticks after they have been outdoors.
The symptoms of Lyme disease depend on the stage of the disease. You may first notice symptoms weeks to months after the tick bite. If the disease isn't treated, it may progress from mild symptoms to serious, long-term disabilities.
- In the first stage, you may have a rash at the site of the tick bite. You may also have a lack of energy or a headache and stiff neck. Sometimes people have no symptoms at this stage.
- In the second stage, symptoms may include memory problems and pain and weakness in the arms and legs.
- In the third stage, symptoms may include swelling and pain (like arthritis) in the joints, not being able to control facial muscles, and numbness and tingling in the hands, feet, or back. You may have heart problems.
If you don't have symptoms during stage 1, your first symptoms may be those found in stage 2 or 3.
When to Call a Doctor
Call your doctor if:
- A tick is attached to your body and you can't remove the entire tick.
- You have a circular red rash that expands over the course of several days, especially if you know you were recently exposed to ticks. You may also have flu-like symptoms, such as fatigue, headache, stiff neck, fever, chills, or body aches.
- You feel very tired or have joint pain (especially with redness and swelling), irregular heartbeats, severe headache, or neck pain.
- You are pregnant or breastfeeding and you think you may have been exposed to ticks.
Exams and Tests
To diagnose early Lyme disease, your doctor will give you a physical exam. You will be asked about your symptoms and any recent exposure to ticks. The clearest sign of infection is an expanding, circular red rash. (This is called erythema migrans.)
Your doctor may do blood tests to confirm that you have Lyme disease. The decision about when to use blood tests depends on if your doctor strongly thinks you have Lyme disease and if the test results will change your treatment. In some cases, your doctor may treat you for Lyme disease without doing any tests.
Lyme disease is often hard to diagnose. Early on, blood tests may not show Lyme disease even though you are infected. At later stages, blood tests may not be able to tell if you have an active infection or a past infection that you recovered from. The symptoms of chronic Lyme disease can be very similar to other illnesses. People may test positive even though something other than Lyme disease is causing their symptoms.
Lyme disease is treated with antibiotics. Most people are treated with antibiotics that are taken by mouth. But sometimes antibiotics through a vein (IV) are needed.
It's important to get treatment for Lyme disease as soon as you can. If it goes untreated, Lyme disease can lead to problems with your skin, joints, nervous system, and heart. These can occur weeks, months, or even years after your tick bite. The problems often get better with antibiotics. But in rare cases, they can last the rest of your life.
Even after successful treatment for Lyme disease, you can get it again. So it's important to keep protecting yourself against tick bites.
- Take your antibiotics as directed. Don't stop taking them just because you feel better. You need to take the full course of antibiotics.
- Ask your doctor if you can take an over-the-counter pain medicine if needed, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve). Read and follow all instructions on the label.
Current as of: July 1, 2021
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Christine Hahn MD - Epidemiology
W. David Colby IV MSc, MD, FRCPC - Infectious Disease