Can Lyme Disease Mimic Rheumatoid Arthritis?
Can Lyme disease mimic rheumatoid arthritis? Yes. Lyme disease can resemble rheumatoid arthritis (RA), causing joint pain, swelling, stiffness, and fatigue. Some patients are initially diagnosed with rheumatoid arthritis before Lyme disease is recognized, while others develop both conditions simultaneously. Distinguishing between these conditions is important because their underlying causes and treatments differ.
Joint pain is one of the most common reasons patients seek medical attention for Lyme disease. Although Lyme arthritis often affects one or a few large joints—particularly the knee—some patients develop symptoms that resemble inflammatory arthritis, making diagnosis challenging.
I frequently evaluate patients whose persistent joint symptoms were initially attributed to rheumatoid arthritis before Lyme disease was considered. I also care for patients with established rheumatoid arthritis who later develop Lyme disease, making diagnosis considerably more complex.
Can Patients Have Both Lyme Disease and Rheumatoid Arthritis?
Yes. Having one condition does not exclude the other.
A 2022 study by Yuskevych and colleagues evaluated 90 patients with rheumatoid arthritis and found that nearly half also tested positive for Lyme disease. Patients with both conditions experienced significantly greater physical disability, joint pain, and impairment in quality of life than patients with rheumatoid arthritis alone.
The authors reported that Borrelia burgdorferi, the bacterium that causes Lyme disease, significantly reduced motor activity and complicated patients’ psychological adaptation to their illness.
Patients with both Lyme arthritis and rheumatoid arthritis experienced worse quality of life, more severe joint pain, and greater functional impairment than patients with rheumatoid arthritis alone.
The investigators also observed lower mental health scores among patients with both conditions. They suggested that recognizing an infectious contributor to arthritis may increase emotional distress compared with having an autoimmune diagnosis alone.
How Lyme Arthritis Differs from Rheumatoid Arthritis
Although Lyme disease and rheumatoid arthritis share overlapping symptoms, several clinical features help distinguish them.
- Lyme arthritis often affects one or several large joints, particularly the knee, and symptoms may migrate between joints.
- Rheumatoid arthritis typically causes persistent, symmetrical inflammation involving the small joints of the hands, wrists, and feet.
- Morning stiffness tends to last longer in rheumatoid arthritis.
- Lyme disease may be accompanied by neurologic symptoms, fatigue, facial palsy, cognitive dysfunction, or a history of tick exposure.
- Some patients have overlapping features, requiring careful clinical evaluation.
Because presentations can overlap, physicians must consider the patient’s history, physical examination, laboratory findings, and likelihood of tick exposure rather than relying on any single symptom.
Laboratory Testing Can Help—but Has Limitations
Laboratory testing may support the diagnosis, but no single test definitively distinguishes Lyme disease from rheumatoid arthritis in every patient.
Patients with rheumatoid arthritis often have positive rheumatoid factor (RF) or anti-cyclic citrullinated peptide (anti-CCP) antibodies, although these tests are not perfect. Lyme disease is generally diagnosed using two-tier antibody testing, which also has important limitations—particularly during early infection.
In patients with longstanding inflammatory arthritis or persistent symptoms, laboratory results should always be interpreted together with the clinical presentation rather than in isolation.
Clinical judgment remains essential. Laboratory tests support—but do not replace—a careful clinical evaluation. Physicians must interpret test results together with the patient’s symptoms, physical examination, and exposure history.
Imaging Differences
Imaging studies may also help distinguish Lyme arthritis from rheumatoid arthritis, although findings can overlap.
In Lyme arthritis, imaging often demonstrates joint effusions and soft tissue inflammation, particularly involving large joints such as the knee. In contrast, longstanding rheumatoid arthritis is more likely to show symmetrical joint-space narrowing, erosions, and chronic synovitis affecting the small joints of the hands and feet.
Imaging findings alone are rarely diagnostic and should always be interpreted in the context of the patient’s clinical history and laboratory evaluation.
Treatment Differs Significantly
Distinguishing Lyme disease from rheumatoid arthritis is important because treatment strategies differ substantially.
Lyme arthritis is generally treated with antibiotics directed against Borrelia burgdorferi. Most patients improve after appropriate antimicrobial therapy, although some continue to experience inflammation that may require additional management.
Rheumatoid arthritis is an autoimmune disease typically treated with disease-modifying antirheumatic drugs (DMARDs), biologic therapies, or corticosteroids to suppress immune-mediated inflammation.
When both conditions coexist, clinicians must determine whether ongoing symptoms reflect persistent infection, autoimmune inflammation, or a combination of both before selecting treatment.
Clinical Perspective
Diagnosing patients with persistent joint pain is not always straightforward. Some individuals initially receive a diagnosis of rheumatoid arthritis before Lyme disease is recognized, while others with established rheumatoid arthritis later acquire Lyme disease after a tick bite.
In my clinical practice, I frequently evaluate patients whose persistent joint symptoms were initially attributed solely to rheumatoid arthritis before Lyme disease was considered. I also care for patients with established rheumatoid arthritis who later develop Lyme disease, making diagnosis considerably more complex.
Because these disorders can overlap, physicians should avoid relying on any single laboratory result or symptom. Instead, the diagnosis should integrate the patient’s history, examination, laboratory findings, imaging studies, and risk of tick exposure.
Clinical Takeaway
Lyme disease can mimic rheumatoid arthritis, and some patients have both conditions simultaneously. Although the disorders share joint pain, stiffness, swelling, and fatigue, careful clinical evaluation can often distinguish them.
Recognizing Lyme disease in patients with inflammatory arthritis is important because treatment differs substantially from rheumatoid arthritis. Missing either diagnosis may delay appropriate care.
Related Articles
Lyme arthritis shares symptoms with several inflammatory and autoimmune conditions. These articles explore diagnosis, treatment, and related clinical challenges.
- Lyme disease protein tricks the immune system, ignites arthritis
- Treatment of Lyme arthritis with disease-modifying antirheumatic drugs
- Will steroid injections help children with Lyme arthritis of the knee?
- Why Lyme disease is commonly misdiagnosed
- Why Lyme disease tests can miss infection
Frequently Asked Questions
Can Lyme disease be mistaken for rheumatoid arthritis?
Yes. Lyme disease can mimic rheumatoid arthritis because both conditions may cause joint pain, swelling, stiffness, and fatigue. A careful clinical evaluation is often needed to distinguish between them.
Can someone have both Lyme disease and rheumatoid arthritis?
Yes. Patients with rheumatoid arthritis can also develop Lyme disease after a tick bite, making diagnosis and treatment more challenging.
Does Lyme disease cause positive rheumatoid factor?
Occasionally. Rheumatoid factor may be positive in some infections, including Lyme disease, so test results should always be interpreted alongside the patient’s clinical findings.
How is Lyme arthritis treated?
Lyme arthritis is typically treated with antibiotics directed against Borrelia burgdorferi. Some patients with persistent joint inflammation after antibiotic treatment may require additional evaluation and management.
References
- Arvikar SL, Steere AC. Diagnosis and treatment of Lyme arthritis. Infect Dis Clin North Am. 2015;29(2):269-280. doi:10.1016/j.idc.2015.02.004.
- Yuskevych VV, Zhulkevych IV, Makhovska OS, Smiyan SI. Assessment of quality of life in patients with Lyme arthritis and rheumatoid arthritis. Reumatologia. 2022;60(1):35-41. doi:10.5114/reum.2022.114352.
- Arvikar SL, Crowley JT, Sulka KB, Steere AC. Autoimmune arthritides, rheumatoid arthritis, psoriatic arthritis, or peripheral spondyloarthritis following Lyme disease. Arthritis Rheumatol. 2017;69(1):194-202.
- Lantos PM, Auwaerter PG, Wormser GP. A systematic review of Borrelia burgdorferi morphologic variants does not support a role in chronic Lyme disease. Clin Infect Dis. 2021;72(4):663-671.
- Cameron DJ, Johnson LB, Maloney EL. Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease. Expert Rev Anti Infect Ther. 2014;12(9):1103-1135.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
I have always heard that lyme arthritis resembles rheumatoid arthritis, so it is another of the lyme mimics, like alzheimers, M.S, chronic fatigue etc. Not to say in any of those conditions that lyme always causes it. In my “rheumatoid” arthritis, it is definitely lyme. And it comes with swelling, leg cramps and varicose veins. A nasty combination. And hard to treat. Means I can’t walk far and have disturbed sleep.
If you have varicose vains and arthritis at the same, it means that you have Bartonella Arthritis, quite different from Lyme Arthritis. It is inflammatory condition caused by systemic, chronic Bartonella infection.
I am not convinced that one tell which arthritis is from which tick borne pathogen
36yrs of being denied by UK NHS that I have Lyme disease even though I had the classic bulls eye mark and positive results from USA and German labs. This has left me in severe pain and damage to knees, hands, feet and back. All UK doctors can say is that it is Arthritis. Anyone any advice please?
My patients have also found it easier in America to find a doctor for any other illness.