Fibromyalgia and Lyme Disease: Can Lyme Disease Be Mistaken for Fibromyalgia?

Lyme disease can resemble fibromyalgia
Fatigue, pain, and brain fog may overlap
Symptoms alone may not distinguish them

Can Lyme disease be mistaken for fibromyalgia? Yes. Fibromyalgia and Lyme disease can share many symptoms, including widespread pain, fatigue, sleep disturbances, headaches, cognitive difficulties, and sensitivity to light, sound, or temperature.

A 2023 Canadian study illustrates how difficult that overlap can be. Researchers studying people with complex and chronic illnesses found that participants considered to have presumptive Lyme disease and those with Lyme-like illnesses had similarly substantial symptom and functional burdens. The questionnaires used in the study did not clearly distinguish the groups.¹

The investigators also found Borrelia antibodies in participants both with and without a previous Lyme disease diagnosis. Importantly, a positive antibody test indicates an immune response to Borrelia; it does not by itself establish that an active infection is causing a patient’s current fibromyalgia-like symptoms.¹

The practical challenge is therefore not to assume that every patient with fibromyalgia has Lyme disease—or that every patient with widespread pain and fatigue can be adequately evaluated from symptoms alone.

How Lyme Disease and Fibromyalgia Overlap

Fibromyalgia is characterized by chronic widespread pain and is commonly accompanied by fatigue, sleep disturbance, headaches, cognitive complaints, and other symptoms.^2,3

Many of these complaints can also occur in Lyme disease. Patients with Lyme disease may report fatigue, muscle and joint pain, headaches, sleep disturbance, cognitive difficulties, and neurologic symptoms.

This overlap becomes particularly challenging when a patient does not recall a tick bite or recognized erythema migrans rash and does not have an obvious objective manifestation such as facial palsy or a swollen knee.

However, the conditions are not interchangeable. Fibromyalgia is a clinical syndrome involving widespread pain and associated symptoms. Lyme disease is an infection caused by Borrelia bacteria. Determining which diagnosis—or combination of diagnoses—best explains an individual patient’s illness requires a broader clinical evaluation.

What Did the Canadian Study Find?

Sanderson and colleagues studied 157 participants in Eastern Canada with complex and chronic illnesses. Participants were placed into intake categories that included presumptive Lyme disease, Lyme-like illness, other illnesses, and healthy controls.¹

The Lyme-like group included patients reporting diagnoses such as fibromyalgia, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), neurologic disorders, and rheumatic conditions.

Participants completed several questionnaires measuring symptoms, health status, and functional impairment. Blood samples were also evaluated for IgG and IgM antibodies to Borrelia burgdorferi using enzyme immunoassay and Western blot testing.¹

The investigators found substantial overlap between the presumptive Lyme disease and Lyme-like illness groups. Both groups reported a profound burden of symptoms and impaired function, and questionnaire results did not clearly separate them.¹

This is clinically important because it demonstrates how difficult it may be to distinguish Lyme disease from other complex chronic illnesses based on symptom questionnaires alone.

What Did Lyme Disease Testing Show?

Two-tier testing identified IgG seropositivity in 17 of the 157 participants (10.8%) and IgM seropositivity in 14 (8.9%). Seropositivity was found both among participants considered to have presumptive Lyme disease and among participants in the other diagnostic categories.¹

More than half of the participants who were IgG seropositive were outside the presumptive Lyme disease group. Among IgG-positive participants without a reported history of Lyme disease, fibromyalgia was the most common individual diagnostic label.¹

The researchers also found no significant differences in the symptom and health questionnaires when comparing seropositive participants in the presumptive Lyme group with seropositive participants in the other illness groups.¹

Instead, a history of tick bite, rash, or other acute manifestations helped differentiate participants who had been categorized as having presumptive Lyme disease.¹

Does a Positive Lyme Test Mean Fibromyalgia Is Caused by Lyme Disease?

No. The Canadian study does not demonstrate that Lyme disease causes fibromyalgia.

Antibodies indicate that the immune system has reacted to Borrelia. They do not necessarily establish when infection occurred, whether viable bacteria remain present, or whether the infection is responsible for a patient’s current symptoms.

This distinction is especially important in a cross-sectional study. The investigators evaluated participants at one point in time and did not attempt to determine whether seropositive participants had active ongoing infection.¹

The study also involved a relatively small and highly selected population of people with complex chronic illnesses. Participants were recruited through patient groups, hospital posters, and clinical sources. The approximately 10% seroprevalence found in this cohort therefore should not be interpreted as the prevalence of Borrelia infection among all people with fibromyalgia, ME/CFS, or other chronic illnesses.¹

Can Lyme Disease Be Mistaken for Fibromyalgia?

Yes. Lyme disease and fibromyalgia can overlap considerably in their clinical presentation.

Both may involve:

• Widespread muscle or musculoskeletal pain
• Fatigue and reduced stamina
• Nonrestorative or disrupted sleep
• Headaches
• Brain fog or difficulty concentrating
• Sensory sensitivity
• Reduced ability to work or perform normal activities

These symptoms are important, but none individually proves that a patient has Lyme disease.

Physicians may therefore consider whether symptoms began after a tick bite, outdoor exposure in a Lyme-endemic area, an unexplained flu-like illness, or an expanding rash. A history of facial palsy, meningitis, radicular pain, arthritis, or other compatible neurologic or inflammatory manifestations may also increase suspicion for Lyme disease.

Laboratory testing can provide additional information, but results need to be interpreted in the context of the patient’s symptoms, exposure history, timing of illness, previous treatment, and physical findings.

Can Lyme Disease and Fibromyalgia Occur Together?

Yes. The presence of one diagnosis does not necessarily exclude the other.

Earlier studies documented fibromyalgia syndromes among some patients evaluated for Lyme disease. Logigian and colleagues described fibromyalgia among patients with chronic neurologic manifestations of Lyme disease, while Dinerman and Steere subsequently reported fibromyalgia occurring in association with Lyme disease.^4,5

These older studies should not be interpreted to mean that fibromyalgia generally results from Lyme disease. They demonstrate instead that fibromyalgia-like syndromes and Lyme disease can occur in the same clinical population and that persistent widespread pain may have more than one possible explanation.

Why Symptoms Alone May Not Be Enough

The 2023 Canadian study adds an important perspective because symptom questionnaires did not clearly distinguish participants considered to have Lyme disease from those with Lyme-like chronic illnesses.¹

That does not make clinical symptoms unimportant. Instead, it emphasizes the need to look beyond a symptom checklist.

A careful evaluation may include:

• Possible tick exposure
• Residence or travel in an endemic area
• History of an expanding rash
• Previous unexplained acute or flu-like illness
• Facial palsy or other cranial neuropathy
• Radicular or other neurologic symptoms
• Objective joint swelling
• Previous Lyme disease testing and its timing
• Previous antibiotic treatment
• Alternative medical explanations for the symptoms

Current Lyme disease tests also have limitations, particularly early in infection and in selected clinical circumstances. A negative test therefore needs to be interpreted alongside the clinical picture rather than viewed in isolation. For a more detailed discussion, see Lyme Disease Test Accuracy: Timing, Limitations, and Clinical Diagnosis.

Treatment When Lyme Disease and Fibromyalgia Are Both Considered

Treatment depends on the diagnosis and the individual patient’s clinical presentation.

Fibromyalgia treatment may include medications, sleep management, physical activity tailored to tolerance, pain management, and treatment of contributing conditions. Medications such as duloxetine, milnacipran, and pregabalin can reduce symptoms in some patients, although response varies and many patients continue to experience pain or other symptoms.^6-8

If Lyme disease is diagnosed, treatment should be individualized according to the patient’s clinical presentation, disease stage, previous treatment, and other relevant factors.

For patients with persistent symptoms after Lyme disease treatment, clinicians may also need to consider multiple possible contributors, including persistent manifestations of Lyme disease, autonomic dysfunction, sleep disorders, other tick-borne infections, neurologic disorders, inflammatory conditions, or unrelated medical problems.

Clinical Perspective

In my clinical practice, I have evaluated men and women who arrived with a diagnosis of fibromyalgia but whose history and clinical presentation led to further evaluation for Lyme disease. Some have experienced meaningful improvement after antimicrobial treatment directed at Lyme disease, while others have not.

This experience does not mean that fibromyalgia should automatically be attributed to Lyme disease. It does reinforce the importance of reconsidering the diagnosis when symptoms persist, evolve, or are accompanied by a history or findings that suggest a tick-borne illness.

The Canadian study provides another reason for caution in both directions. Patients with presumptive Lyme disease and those with Lyme-like chronic illnesses can look remarkably similar when evaluated primarily by symptom burden.¹

A diagnosis should therefore not be made—or dismissed—on the basis of fatigue, widespread pain, brain fog, or a laboratory result considered in isolation.

Frequently Asked Questions

Can Lyme disease be mistaken for fibromyalgia?

Yes. Lyme disease and fibromyalgia can share symptoms including widespread pain, fatigue, poor sleep, headaches, and cognitive difficulties. Exposure history, physical findings, laboratory testing, and the course of illness can help distinguish the conditions.

Can Lyme disease cause fibromyalgia?

Lyme disease and fibromyalgia have been reported together, but the available evidence does not establish that Lyme disease generally causes fibromyalgia. Some patients with Lyme disease may develop persistent widespread pain or meet fibromyalgia criteria, while many people with fibromyalgia have no evidence of Lyme disease.

Does a positive Lyme test prove that chronic pain is caused by Lyme disease?

No. A positive antibody test demonstrates an immune response to Borrelia but does not by itself establish that active infection is responsible for a patient’s current symptoms. The result needs to be interpreted within the complete clinical picture.

How do doctors tell Lyme disease from fibromyalgia?

Doctors consider the pattern and timing of symptoms, possible tick exposure, previous rash or acute illness, objective neurologic or joint findings, laboratory results, previous treatment, and alternative diagnoses. No single symptom reliably distinguishes every patient with Lyme disease from every patient with fibromyalgia.

Can someone have both Lyme disease and fibromyalgia?

Yes. Lyme disease and fibromyalgia-like syndromes have been reported in the same patients. Having one diagnosis does not automatically exclude the other.

Clinical Takeaway

Lyme disease and fibromyalgia can produce remarkably similar patterns of pain, fatigue, sleep disturbance, cognitive difficulty, and reduced function.

The 2023 Canadian study found substantial symptom overlap between participants considered to have presumptive Lyme disease and those with Lyme-like chronic illnesses. It also identified Borrelia seropositivity across diagnostic categories.¹

These findings do not demonstrate that Lyme disease causes fibromyalgia. They show why symptoms and antibody results need to be interpreted within a broader clinical evaluation.

For patients with persistent or evolving symptoms, particularly when there is plausible tick exposure or compatible neurologic, rheumatologic, or other clinical findings, reconsidering the differential diagnosis may be appropriate.

Related Articles

Learn more about Lyme disease symptoms, testing, and persistent illness:

Lyme Disease Symptoms: Why They Come and Go

Lyme Disease Test Accuracy: Timing, Limitations, and Clinical Diagnosis

Persistent Lyme Disease: Why Symptoms Continue After Treatment

Brain Fog and Lyme Disease

Persistent Lyme Disease Mechanisms

References

1. Sanderson VP, Miller JC, Bamm VV, Tilak M, Lloyd VK, Singh-Ranger G, Wills MKB. Profiling disease burden and Borrelia seroprevalence in Canadians with complex and chronic illness. PLoS One. 2023;18(11):e0291382.
2. Cassisi G, Sarzi-Puttini P, Alciati A, et al. Symptoms and signs in fibromyalgia syndrome. Reumatismo. 2008;60(Suppl 1):15-24.
3. Wolfe F, Smythe HA, Yunus MB, et al. The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia: Report of the Multicenter Criteria Committee. Arthritis Rheum. 1990;33(2):160-172.
4. Logigian EL, Kaplan RF, Steere AC. Chronic neurologic manifestations of Lyme disease. N Engl J Med. 1990;323(21):1438-1444.
5. Dinerman H, Steere AC. Lyme disease associated with fibromyalgia. Ann Intern Med. 1992;117(4):281-285.
6. Bradley LA, Wohlreich MM, Wang F, et al. Pain response profile of patients with fibromyalgia treated with duloxetine. Clin J Pain. 2010;26(6):498-504.
7. Vitton O, Gendreau M, Gendreau J, Kranzler J, Rao SG. A double-blind placebo-controlled trial of milnacipran in the treatment of fibromyalgia. Hum Psychopharmacol. 2004;19(Suppl 1):S27-S35.
8. Straube S, Derry S, Moore RA, McQuay HJ. Pregabalin in fibromyalgia: Meta-analysis of efficacy and safety from company clinical trial reports. Rheumatology (Oxford). 2010;49(4):706-715.
9. Steere AC, Malawista SE, Snydman DR, et al. Lyme arthritis: An epidemic of oligoarticular arthritis in children and adults in three Connecticut communities. Arthritis Rheum. 1977;20(1):7-17.
10. Milewski MD, Cruz AI Jr, Miller CP, Peterson AT, Smith BG. Lyme arthritis in children presenting with joint effusions. J Bone Joint Surg Am. 2011;93(3):252-260.
11. Jennings F, Lambert E, Fredericson M. Rheumatic diseases presenting as sports-related injuries. Sports Med. 2008;38(11):917-930.

This article is for educational purposes only and is not a substitute for individualized medical advice, diagnosis, or treatment.

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