Lyme arthritis is a chronic condition that occurs when the bacteria that cause Lyme disease lead to inflammation of joint tissues. If the infection is not treated, permanent joint damage can occur. As many as 300,000 people will become infected with Lyme disease each year, with about 25% of those cases developing Lyme arthritis.

Symptoms

Lyme arthritis is considered one of the most common chronic conditions associated with Lyme disease. Typical symptoms of Lyme disease occur hours to weeks following the infection, with Lyme arthritis typically presenting itself any time within the first four weeks to several months after the initial infection.

It causes swelling and pain in one or more of the following joints:

  • KneesShouldersAnklesElbowsJawWristsHips

Lyme arthritis usually involves only a few joints, and it is likely to be asymmetrical—it does not affect both sides of the body the same way.

With Lyme arthritis, the joints tend to swell up significantly and the pain and swelling tend to come and go.

Sometimes Lyme arthritis can appear similar to other types of arthritis, such as rheumatoid arthritis osteoarthritis, and it may not be immediately recognized as Lyme arthritis unless you know that you have Lyme disease or that you had a tick bite.

The quicker you receive treatment for Lyme disease, the better. If you suspect you may be developing Lyme disease-induced arthritis, contact your healthcare provider right away to discuss testing and treatment options.

Causes

Lyme arthritis occurs when Lyme disease bacteria enter joint tissues and cause inflammation. The only way to contract Lyme disease is via a bite from an infected tick. The bacterium responsible for the infection is commonly Borrelia burgdorferii. However, rare instances of the infection have been caused by Borrelia mayonii.

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The Borrelia bacterium is a type of spirochete that invades all areas of the body once it enters the bloodstream. Since the Borrelia bacteria invade the sensitive tissues that line the joints, they can cause damage to the cartilage, resulting in Lyme arthritis.

In the United States, Lyme disease is the most common vector-borne illness and is typically found in black-legged ticks.

Roughly 60% of those with untreated Lyme disease will develop Lyme arthritis. For most, Lyme arthritis is highly treatable with antibiotics within 30 days. However, in some cases, the bacteria may continue to damage the tissues even after Lyme disease is treated.

Chronic infections with the Lyme disease-causing bacteria can sometimes occur after treatment because of the bacteria’s ability to hide among vulnerable tissues within the body. They do so by attaching themselves to cells using a special surface protein.

Bacterial Structure

The unique peptidoglycan structure of the Borrelia bacteria contributes to this organism’s ability to cause chronic Lyme arthritis. A peptidoglycan cell wall matrix is made up of proteins and sugars that are designed to keep the cells intact.

Most types of bacteria reuse their peptidoglycans, Borrelia bacteria do not. They shed them as they replicate, leaving peptidoglycans throughout the body. This leads to an inflammatory immune response that rids the body of the remaining peptidoglycans—this immune process also produces inflammation around the joints, which leads to the symptoms of Lyme arthritis.

Diagnosis

The first step in the diagnosis of Lyme arthritis is usually identifying a Lyme disease infection through a physical examination. A bull’s eye type rash often appears at the site of the bite, and it can be visible with a physical examination early in the infection cycle.

Other tests can also be done for the diagnosis of Lyme disease.

Serologic Testing

There are two different serology tests that can help identify Lyme disease:

  • Enzyme-linked immunosorbent assay (ELISA test): A sample of blood will be taken to identify the presence of antibodies. Western Blot (WB): This test can confirm a positive diagnosis.

Polymerase Chain Reaction (PCR)

The PCR test is used as further diagnostic support following a positive serology result for Lyme disease.

The PCR testing method is done using synovial fluid (joint fluid) to help identify the presence of the bacteria prior to treatment.

Once treatment with antibiotics starts, a PCR test will not be as effective.

Joint Aspiration

To help rule out other types of arthritic conditions, joint aspiration may be conducted. This test is done using samples of synovial fluid.

Synovial fluid may show characteristics of other forms of arthritis that could be causing your joint pain and damage.

Imaging and Other Tests

In Lyme arthritis, the joints and their surrounding tissues can become inflamed, swollen, and damaged.

Sometimes, imaging tests, such as MRI or ultrasound, can help your healthcare provider visualize your joints to assess for damage and any other abnormalities.

Treatment

Lyme arthritis is usually treated with a four-week course of oral antibiotics. If you have persistent joint inflammation and pain after your first course of antibiotics, you may need a second course of antibiotics. Treatment of Lyme arthritis may happen at the same time as Lyme disease treatment.

The antibiotics typically used include:

  • DoxycyclineAmoxicillinCefuroxime

Sometimes if Lyme arthritis is persistent, intravenous antibiotic therapy using ceftriaxone may be administered.

For the 10% of people who don’t respond to antibiotic treatment at all, other forms of treatment may be needed to help curb the inflammation. It was found that certain immune-dampening medications such as methotrexate and TNF (tumor necrosis factor) inhibitors could help those with persistent Lyme arthritis.

Prognosis

In the majority of Lyme arthritis cases, the first 30-day round of antibiotics or the following four-week IV treatment leads to a complete resolution of symptoms.

When treatment is postponed for too long, permanent damage to the joints and tissues can occur. In these situations, the damage can’t be reversed, and pain management, usually with over-the-counter medications, like nonsteroidal anti-inflammatory drugs (NSAIDs), is often helpful for controlling symptoms.  

Coping

Pain and swelling can often be managed with medication. If your symptoms persist, contact your healthcare provider to discuss further treatment options.

If the joint pain is limiting your mobility, you might be instructed to walk with assistance and avoid overuse of the joints that could lead to worsened damage and further inflammation.

Prevention

Preventing a tick bite is the most effective way to prevent lyme arthritis. Blacklegged ticks live in moist and humid environments, particularly in and near wooded or grassy areas.

When walking in these areas:

  • Walk in the center of trails and avoid walking through tall bushes or other plantsUse insect repellents like bug sprays with DEET or oils of lemon eucalyptusWear loose-fitted clothing that covers all areas of the body where a tick may be able to latch on to

The Environmental Protection Agency has an online tool to help you find an insect repellent that works best for you and your family.

A Word from Verywell

Dealing with Lyme arthritis can be difficult, especially if you don’t know you have Lyme disease in the first place. Treatment for Lyme arthritis is generally effective, and early recognition and interventions lead to a full recovery in the majority of cases. If you recently spent some time outdoors and experience joint pain and swelling, see your healthcare provider so you can be evaluated for Lyme disease and Lyme arthritis.