Tick-borne diseases, such as Lyme disease, are on the rise in people and dogs. Reported cases in people in the U.S. increased from about 12,000 annually in 1995 to approximately 35,000 in 2019, according to the Centers for Disease Control and Prevention. However, not all diagnosed cases are reported and the CDC believes the true number of human infections is likely closer to 476,000 per year.

The U.S. Food and Drug Administration regulates products that are used to help prevent, diagnose, and treat this complex disease. 

Who Gets Lyme Disease, What Time of Year?

Lyme disease is a bacterial infection most commonly transmitted via the bite of infected ticks, which attach to any part of the body. 

The CDC recommends you check your dog daily, especially after they spend time outdoors. Pay particular attention to the collar area and around the eyelids, ears, tail, under the front legs, and between the back legs and toes. 

On people, you will most often find ticks in moist or hairy areas such as the groin, armpits, scalp, and other hard-to-see areas of the body. And while everyone is susceptible to tick bites, campers, hikers, and people who work in gardens and other woody, and brushy areas with high grass and leaf litter, are at the greatest risk of tick bites. As many a suburban gardener can attest, with the expansion of the suburbs and a push to conserve wooded areas, deer populations are thriving. Deer are important sources of blood for ticks and are important to tick survival and movement to new areas, increasing the contact between people and ticks that carry the bacteria. Read more about the lifecycle of the bacteria and how it is transmitted to people and dogs.

In most cases, a tick must be attached for 36 to 48 hours or more before the Lyme disease bacterium can be transmitted. If you remove it within 24 hours, the risk is greatly reduced. Symptoms of Lyme disease may take 3-30 days or longer to appear.

In the majority of cases, tick bites are reported in the summer months when ticks are most active and people spend more time outdoors. But this can extend into the warmer months of early autumn, or even late winter if temperatures are unusually high. Similarly, a mild winter can allow ticks and other insects to thrive and emerge earlier than usual.

How to Safely Remove a Tick

1. Using fine-tipped tweezers, grasp the tick as close to the skin’s surface as possible.
2. Pull upward with steady, even pressure. Don't twist or jerk the tick. Your goal is to remove the entire tick, ideally in one piece, including the mouth parts embedded under the skin.
3. Thoroughly clean the bite area and your hands with rubbing alcohol, an iodine scrub, or soap and water.

Not all ticks carry Lyme disease, and some ticks carry other diseases. To avoid infecting yourself, never crush a tick with your fingers.

Lyme Disease in People

Prevention

What can I do to prevent Lyme disease?

• Avoid wooded, brushy, and grassy areas, especially during warmer months (April – September), although tick exposure can occur anytime.
• Wear light-colored clothing so that you can see ticks that get on you.
• Treat clothing and gear with products containing 0.5% permethrin.
• Apply insect repellents on uncovered skin, and ensure the products are registered by the Environmental Protection Agency.
• Wear long pants and long-sleeved shirts, and shoes that cover the entire foot.
• Tuck pant legs into socks or shoes, and tuck shirts into pants.
• Wear a hat for extra protection.
• Walk in the center of trails to avoid brush and grass.
• Remove your clothing after being outdoors, and wash and dry them at high temperatures.
• Do a careful body check for ticks after outdoor activities.

There are no licensed vaccines available in the U.S. to aid in the prevention of Lyme disease in people.

Symptoms and Stages

Symptoms of early-stage Lyme disease include:

• muscle and joint aches
• headache
• fever
• chills
• fatigue
• swollen lymph nodes

Another common symptom of Lyme disease is a rash (referred to as “Erythema migrans”). As many as 80% of infected people may develop a rash, however the characteristic “bull's-eye” rash appears only 20% of the time. 

Later-stage symptoms may not appear until weeks or months after a tick bite. They include:

• irregular heartbeat and/or heart palpitations 
• arthritis (usually seen as pain and swelling in large joints, especially the knee)
• nervous system abnormalities

When left untreated, the bacterial infection can spread to joints, the heart, and the nervous system and cause permanent damage. Lyme disease is rarely fatal. 

However, if not treated properly, Lyme disease can become a chronic illness where symptoms might continue for weeks, months, or even years after the initial tick bite.

Lyme Disease in Dogs

Dogs can get Lyme disease, too. Typical symptoms in dogs include swollen joints and lameness, fever, and loss of appetite. Experts in the FDA’s Center for Veterinary Medicine say dogs with Lyme disease occasionally develop serious kidney disease that can be fatal.

There are ways you can reduce your dog’s risk for tick bites and Lyme disease, which also reduces the risk of infection for you. 

• Regularly check your dog for ticks. 
• Avoid allowing your dog to roam in tick-infested areas. 
• Treat your dog year-round with topical, oral and/or collar tick products. Talk to your veterinarian about which product is best for your dog.

Lyme disease occurs much less frequently in cats than in dogs, and cats’ susceptibility to the disease continues to be the subject of research. However, the same precautions for dogs apply to cats, especially if your cat goes outside, because ticks on cats can be transferred to people and ticks carry other diseases besides Lyme disease that are harmful to cats.

There are several FDA-approved products that treat and control tick infestations. A couple of tick products are also approved in dogs to specifically prevent infections with the bacteria that causes Lyme disease by killing the ticks that carry the bacteria.

Lyme disease vaccines are available for dogs, but not for cats. Talk to your veterinarian to see if vaccination is appropriate for your dog. 

Lyme Disease Tests and Treatment

If you think you or your dog may have Lyme disease, contact your physician or veterinarian right away. 

Your doctor or veterinarian may test for Lyme disease, and/or they may immediately begin antibiotic treatment, depending on the symptoms you or your dog exhibit. 

Most blood tests check for the antibodies produced by the body to fight Lyme disease. CDC experts report it may take several weeks after a tick bite for initial antibodies to develop. Because of this, the blood tests may not be accurate if done soon after a tick bite. 

For this reason, your doctor or veterinarian may recommend treatment with antibiotics before the diagnostic tests are complete. According to the CDC and other experts, people treated with appropriate antibiotics in the early stages of Lyme disease usually recover rapidly and completely. 

In dogs, the more subtle early stages of Lyme disease often go unnoticed. Even if your dog appears healthy, your veterinarian may recommend yearly screening for Lyme disease, especially if you live in an area where Lyme disease is common. If your dog’s blood test is positive, your veterinarian may recommend additional testing, such as a urinalysis.

What is "chronic Lyme disease?"

Lyme disease is an infection caused by the bacterium Borrelia burgdorferi. In the majority of cases, it is successfully treated with oral antibiotics. In some patients, symptoms, such as fatigue, pain and joint and muscle aches, persist even after treatment, a condition termed “Post Treatment Lyme Disease Syndrome (PTLDS)”.

The term “chronic Lyme disease” (CLD) has been used to describe people with different illnesses. While the term is sometimes used to describe illness in patients with Lyme disease, it has also been used to describe symptoms in people who have no clinical or diagnostic evidence of a current or past infection with B. burgdorferi . Because of the confusion in how the term CLD is employed, and the lack of a clearly defined clinical definition, many experts in this field do not support its use.

How is Lyme disease treated?

For early Lyme disease, a short course of oral antibiotics such as doxycycline or amoxicillin is curative in the majority of the cases. In more complicated cases, Lyme disease can usually be successfully treated with three to four weeks of antibiotic therapy.

In patients who have non-specific symptoms after being treated for Lyme disease and who have no evidence of active infection (patients with PTLDS), studies have shown that more antibiotic therapy is not helpful and can be dangerous.

People treated with appropriate antibiotics in the early stages of Lyme disease usually recover rapidly and completely. Early diagnosis and proper antibiotic treatment of Lyme disease can help prevent late Lyme disease.

Treatment regimens listed in the following table are for the erythema migrans rash, the most common manifestation of early Lyme disease. These regimens may need to be adjusted depending on a person’s age, medical history, underlying health conditions, pregnancy status, or allergies. Consult an infectious disease specialist regarding individual patient treatment decisions.

*When different durations of antibiotics are shown to be effective for the treatment of Lyme disease, the shorter duration is preferred to minimize adverse effects, including infectious diarrhea and antimicrobial resistance.

NOTE: For people intolerant of amoxicillin, doxycycline, and cefuroxime, the macrolide azithromycin may be used, although it is less effective. People treated with azithromycin should be closely monitored to ensure that symptoms resolve.

What is Lyme arthritis?

Lyme arthritis occurs when Lyme disease bacteria enter joint tissue and cause inflammation. If left untreated, permanent damage to the joint can occur. Lyme arthritis accounts for approximately one out of every four Lyme disease cases reported to CDC. Because of reporting practices, this statistic may overstate the frequency of arthritis among patients seen in routine clinical practice.

What are the symptoms?

The main feature of Lyme arthritis is obvious swelling of one or a few joints. While the knees are affected most often, other large joints such as the shoulder, ankle, elbow, jaw, wrist, and hip can also be involved. The joint may feel warm to the touch or cause pain during movement. Joint swelling can come and go or move between joints, and it may be difficult to detect in the shoulder, hip, or jaw. Lyme arthritis typically develops within one to a few months after infection.

How is it treated?

An initial episode of Lyme arthritis should be treated with a 4-week course of oral antibiotics.  Patients with persistent joint inflammation and pain after the first course of antibiotics may require a second course (see tables below). In some cases, joint swelling and pain can persist or recur after two courses of antibiotics. The cause of persistent arthritis is unknown but is thought to be driven by immunologic factors. Additional antibiotics have not been shown to improve these symptoms, and patient referral to a rheumatologist should be considered.

Is Lyme arthritis permanent?

People who do not receive prompt treatment for Lyme arthritis are at risk of developing permanent joint damage.

Key Points for Healthcare Providers

1. Antibody-based Lyme disease tests have excellent sensitivity in patients with Lyme arthritis. PCR can be used as an adjunctive diagnostic test to identify DNA in synovial fluid but should not be the first lab test used.
2. Lyme arthritis can be mistaken for septic arthritis, especially in children. Whereas septic arthritis may require surgical intervention, Lyme arthritis generally does not.
3. Talk to patients about tick bite prevention.

Antibiotic Treatment of Lyme Arthritis

These regimens may need to be adjusted depending on a person’s age, medical history, underlying health conditions, pregnancy status, or allergies. Consult an infectious disease specialist regarding individual patient treatment decisions.

Table 1. Oral antibiotic regimens for Lyme arthritis.*

* For patients with an initial episode of Lyme arthritis, a full course of oral antibiotics are recommended. For patients with improving but persistent symptoms after an initial course of oral antibiotics, a second course of the same oral antibiotic or observation alone can be considered.

Table 2. Parenteral antibiotic regimens for Lyme arthritis.†

†Intravenous ceftriaxone is the preferred regimen for the second course of antibiotics for patients without any response after the initial course of antibiotics.

What is Lyme carditis?

Lyme carditis occurs when Lyme disease bacteria enter the tissues of the heart. This can interfere with the normal movement of electrical signals from the heart’s upper to lower chambers, a process that coordinates the beating of the heart. The result is something physicians call “heart block,” which can vary in degree and change rapidly.  Lyme carditis occurs in approximately one out of every hundred Lyme disease cases reported to CDC.

What are the symptoms?

Lyme carditis can cause light-headedness, fainting, shortness of breath, heart palpitations, or chest pain. Patients with Lyme carditis usually have other symptoms such as fever and body aches, and they may have more specific symptoms of Lyme disease, such as the erythema migrans rash.

How is it treated?

Lyme carditis can either be treated with oral or intravenous (IV) antibiotics, depending on severity (see tables below). Some patients might need a temporary pacemaker. Patients generally recover within 1-6 weeks.

Can it be fatal?

Yes. Between 1985 and 2019, eleven cases of fatal Lyme carditis were reported worldwide.

Key Points for Healthcare Providers

1. Ask all patients with suspected Lyme disease about cardiac symptoms, e.g., palpitations, chest pain, light headedness, fainting, shortness of breath, and difficulty breathing with exertion.
2. Ask patients with acute, unexplained cardiac symptoms about possible tick exposure and symptoms of Lyme disease.
3. Treat patients with suspected Lyme carditis with appropriate antibiotics immediately – do not wait for Lyme disease test results. Patients with suspected severe Lyme carditis require immediate hospitalization for cardiac monitoring and intravenous antibiotics.
4. Talk to patients about tick bite prevention.

Antibiotic Treatment of Lyme Carditis

Table 1. Mild (1^st degree AV block with PR interval 300 milliseconds)

Table 2. Severe (symptomatic, 1^st degree AV block with PR interval ≥300 milliseconds, 2^nd or 3^rd degree AV block)*

*After resolution of symptoms and high-grade AV block, consider transitioning to oral antibiotics to complete treatment course (Table 1).

What is neurologic Lyme disease?

Neurologic symptoms of Lyme disease occur when the Lyme disease bacteria affect the peripheral or central nervous systems.

• Cranial nerve involvement: When the cranial nerves are affected, facial palsy (droop) can occur on one or both sides of the face.
• Peripheral nerve involvement: When the peripheral nerves are affected, patients can develop radiculoneuropathy which can cause numbness, tingling, “shooting” pain, or weakness in the arms or legs.
• Central nervous system involvement: When the central nervous system is affected, Lyme meningitis can cause fever, headache, sensitivity to light, and stiff neck.

Out of every 100 patients whose cases are reported to CDC, 9 have facial palsy, 4 have radiculopathy, and 3 have meningitis or encephalitis. Because of reporting practices, this statistic may overestimate how often these manifestations are seen by clinicians.

What are the symptoms?

Neurological complications most often occur in early disseminated Lyme disease, with numbness, pain, weakness, facial palsy/droop (paralysis of the facial muscles), visual disturbances, and meningitis symptoms such as fever, stiff neck, and severe headache.

How is it treated?

Facial palsy is treated with oral antibiotics and Lyme meningitis/radiculoneuritis can either be treated with oral or intravenous antibiotics, depending on severity. Most people with Lyme disease respond well to antibiotics and fully recover. Varying degrees of permanent nervous system damage may develop in people who do not receive treatment in the early stages of illness and who develop late-stage Lyme disease.

Key Points for Healthcare Providers

1. In patients with facial palsy who are unable to close one or both eyes, eye drops or an eye patch may be needed to prevent dry eyes.
2. Neurologic symptoms do not necessarily indicate central nervous system infection in a patient with Lyme disease.
3. Two-step serologic testing for Lyme disease is the recommended diagnostic test for neurologic Lyme disease.
4. Cerebral spinal fluid analysis is not necessary to diagnose Lyme meningitis, but can help exclude other causes of illness, such as bacterial meningitis.
5. Consider Lyme radiculoneuritis in patients who report severe limb or truncal radicular pain without preceding trauma who live in or who have traveled to Lyme-endemic areas.
6. Talk to patients about tick bite prevention.

Antibiotic Treatment of Neurologic Lyme Disease

These regimens may need to be adjusted depending on a person’s age, medical history, underlying health conditions, pregnancy status, or allergies. Consult an infectious disease specialist regarding individual patient treatment decisions.

Table 1. Facial palsy

Table 2. Lyme meningitis or radiculoneuritis

* Oral therapy can be substituted when the patient is stabilized or discharged to complete the course.

Lyme disease is caused by infection with the bacterium Borrelia burgdorferi. Although most cases of Lyme disease can be cured with a 2- to 4-week course of oral antibiotics, patients can sometimes have symptoms of pain, fatigue, or difficulty thinking that lasts for more than 6 months after they finish treatment. This condition is called Post-Treatment Lyme Disease Syndrome (PTLDS).

Why some patients experience PTLDS is not known. Some experts believe that Borrelia burgdorferi can trigger an “auto-immune” response causing symptoms that last well after the infection itself is gone. Auto–immune responses are known to occur following other infections, including campylobacter (Guillain-Barré syndrome), chlamydia (reactive arthritis), and strep throat (rheumatic heart disease). Other experts hypothesize that PTLDS results from a persistent but difficult to detect infection. Finally, some believe that the symptoms of PTLDS are due to other causes unrelated to the patient’s Borrelia burgdorferi infection.

Unfortunately, there is no proven treatment for PTLDS. Although short-term antibiotic treatment is a proven treatment for early Lyme disease, studies funded by the National Institutes of Health (NIH) have found that long-term outcomes are no better for patients who received additional prolonged antibiotic treatment than for patients who received placebo. Long-term antibiotic treatment for Lyme disease has been associated with serious, sometimes deadly complications, as described in the links below.

Patients with PTLDS usually get better over time, but it can take many months to feel completely well. If you have been treated for Lyme disease and still feel unwell, see your healthcare provider to discuss additional options for managing your symptoms. If you are considering long-term antibiotic treatment for ongoing symptoms associated with a Lyme disease infection, please talk to your healthcare provider about the possible risks of such treatment.