Lyme Disease or Rheumatoid Arthritis? How to Tell the Difference
Lyme disease can mimic rheumatoid arthritis, causing joint pain, stiffness, swelling, and fatigue.
But Lyme disease is driven by infection—not autoimmune inflammation.
Joint pain. Morning stiffness. Fatigue.
Is it rheumatoid arthritis—or could it be Lyme disease?
These two conditions can look remarkably similar, yet the underlying cause—and treatment approach—may be entirely different.
Why Lyme Disease Is Mistaken for Rheumatoid Arthritis
Lyme disease can present with symptoms that closely resemble rheumatoid arthritis, including:
- Joint pain and swelling
- Morning stiffness
- Reduced mobility
- Fatigue
Because of this overlap, some patients are initially diagnosed with rheumatoid arthritis when Lyme disease is the underlying cause.
See our overview of Lyme arthritis.
Key Differences Between Lyme Disease and Rheumatoid Arthritis
- Lyme disease: Caused by infection with Borrelia burgdorferi
- Rheumatoid arthritis: An autoimmune condition
Lyme arthritis often affects one or a few joints at a time, while rheumatoid arthritis more commonly presents with symmetrical joint involvement.
Symptoms that fluctuate or migrate between joints may raise suspicion for Lyme disease.
Learn more about why Lyme symptoms come and go.
When Both Conditions Occur Together
In some cases, Lyme disease and rheumatoid arthritis may coexist.
In the study “Assessment of quality of life in patients with Lyme arthritis and rheumatoid arthritis”, Yuskevych and colleagues surveyed 90 patients with rheumatoid arthritis treated at a rheumatology clinic.
Nearly 50% of the patients with rheumatoid arthritis also tested positive for Lyme disease.
The authors found that the presence of Borrelia burgdorferi significantly reduced motor activity and complicated psychological adaptation to the disease.
Patients with both conditions experienced:
- More severe joint pain
- Reduced physical activity
- Greater functional impairment
- Worse quality of life
Patients with Lyme arthritis and rheumatoid arthritis had worse quality of life compared to patients with rheumatoid arthritis alone.
The study also noted substantial mental health burden.
The authors suggested that awareness of an infectious contribution to chronic joint disease may contribute to psychological distress and depressive symptoms.
Why Diagnosis Is Often Delayed
Lyme disease is frequently overlooked when symptoms resemble autoimmune conditions.
When joint symptoms do not respond as expected to standard rheumatoid arthritis treatments, it may be important to consider alternative explanations.
This contributes to delayed Lyme disease diagnosis.
Symptoms that do not follow a typical autoimmune pattern may point toward infection rather than autoimmune disease.
How to Approach Persistent Joint Symptoms
When joint pain is persistent or unexplained, clinicians may consider:
- Exposure risk to ticks
- Fluctuating or migratory symptoms
- Lack of response to standard autoimmune therapy
- Coexisting infectious and inflammatory conditions
See the broader Lyme disease symptoms guide.
Frequently Asked Questions
Can Lyme disease look like rheumatoid arthritis?
Yes. Lyme disease can mimic rheumatoid arthritis with joint pain, stiffness, swelling, and fatigue.
What is the difference between Lyme arthritis and rheumatoid arthritis?
Lyme arthritis is caused by infection, while rheumatoid arthritis is an autoimmune condition.
Can Lyme disease and rheumatoid arthritis occur together?
Yes. Some patients may have both conditions simultaneously.
Why is Lyme disease mistaken for rheumatoid arthritis?
Both conditions can cause joint pain, stiffness, swelling, and reduced mobility, leading to diagnostic confusion.
When should Lyme disease be considered in arthritis patients?
Lyme disease should be considered when symptoms fluctuate, do not follow a typical autoimmune pattern, or respond poorly to standard rheumatoid arthritis treatment.
Clinical Takeaway
I often see patients with both a rheumatologic condition and Lyme disease.
Some patients initially believed to have a flare of rheumatoid arthritis were later found to have symptoms related to Lyme disease.
Lyme disease can closely resemble rheumatoid arthritis—and in some cases, both conditions may coexist.
When joint symptoms are persistent, atypical, migratory, or unresponsive to treatment, Lyme disease should remain part of the differential diagnosis.
Recognizing the overlap between infection and autoimmune disease may help reduce delayed diagnosis and improve patient outcomes.
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Neurologic Lyme Disease
References
- 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
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.