Fibromyalgia vs Lyme Disease: Could Infection Be Missed?

Fibromyalgia vs Lyme disease is a critical diagnostic challenge, as both conditions share overlapping symptoms that can lead to missed or delayed diagnosis. After decades of treating Lyme disease, I have seen patients initially diagnosed with fibromyalgia improve when underlying infection is addressed.

This overlap raises an important question: could some fibromyalgia cases represent undiagnosed Lyme disease or co-infections?

The symptom overlap between these conditions can lead to missed or delayed diagnosis, particularly when infection is not considered. :contentReference[oaicite:0]{index=0}

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Symptom Overlap Between Fibromyalgia and Lyme Disease

Fibromyalgia and Lyme disease share many clinical features:

• Muscle pain
• Fatigue
• Sleep disturbances
• Gastrointestinal complaints
• Difficulty concentrating
• Headaches
• Sensitivity to temperature, light, and sound

Women are disproportionately diagnosed with fibromyalgia. According to the National Institutes of Health, between 80% and 90% of individuals diagnosed with fibromyalgia are women.

This raises important questions about whether some patients may have an underlying infectious component.

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Limited Effectiveness of Fibromyalgia Treatments

Standard fibromyalgia treatments do not always lead to full symptom resolution.

Studies have shown:

• Duloxetine (Cymbalta): ~30% more effective than placebo
• Milnacipran (Savella): ~50% more effective than placebo
• Pregabalin (Lyrica): improves pain and sleep, but only a minority achieve substantial relief

These outcomes suggest that alternative explanations for symptoms—including infection—should be considered in some patients.

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Diagnostic Challenges

It remains difficult to rule out Lyme disease in patients diagnosed with fibromyalgia.

Symptoms such as fatigue, insomnia, and widespread pain are common to both conditions.

Additionally, fibromyalgia “trigger points” may overlap with findings in Lyme disease, including:

• Synovitis
• Bursitis
• Sacroiliitis

Limitations in current Lyme disease testing further complicate the diagnostic process.

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Evidence of Overlap

Research supports an overlap between fibromyalgia and Lyme disease:

• 15% (4 of 27) of chronic neurologic Lyme patients also had fibromyalgia
• 12% (3 of 25) of Lyme patients in a rheumatology clinic had fibromyalgia
• 44% (4 of 9) of fibromyalgia patients had abnormal cerebrospinal fluid findings, including evidence of Borrelia burgdorferi

These findings suggest that some patients may have overlapping or misclassified conditions.

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Clinical Takeaway

Patients diagnosed with fibromyalgia may, in some cases, have symptoms consistent with Lyme disease.

When symptoms are resistant to standard treatment, clinicians should consider the possibility of underlying infection—particularly in patients with outdoor exposure or those living in endemic areas.

In clinical practice, some patients initially diagnosed with fibromyalgia respond to antimicrobial therapy in ways similar to those with confirmed Lyme disease.

This highlights the importance of maintaining a broad differential diagnosis.

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Frequently Asked Questions

Can Lyme disease be misdiagnosed as fibromyalgia?
Yes. Lyme disease and fibromyalgia share symptoms including muscle pain, fatigue, sleep disturbances, and cognitive difficulties, which can lead to diagnostic confusion.

Can someone have both Lyme disease and fibromyalgia?
Yes. Studies suggest that 12–15% of Lyme disease patients also meet fibromyalgia criteria, and some fibromyalgia patients show abnormal spinal fluid findings.

Should fibromyalgia patients be tested for Lyme disease?
Testing should be considered when symptoms are resistant to treatment, appear suddenly, or when patients have exposure risk in endemic areas.

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Related Reading

• Lyme Disease Misdiagnosis: Why It Happens and What Patients Need to Know
• Why Does Lyme Disease Mimic MS or Fibromyalgia?
• Chronic Pain and Lyme Disease
• Lyme Disease Fatigue

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References

1. Bradley LA et al. Clin J Pain, 2010.
2. Vitton O et al. Hum Psychopharmacol, 2004.
3. Straube S et al. Rheumatology, 2010.
4. Cassisi G et al. Reumatismo, 2008.
5. Wolfe F et al. Arthritis Rheum, 1990.
6. Steere AC et al. Arthritis Rheum, 1977.
7. Steere AC et al. Zentralbl Bakteriol, 1986.
8. Milewski MD et al. J Bone Joint Surg Am, 2011.
9. Jennings F et al. Sports Med, 2008.
10. Logigian EL et al. N Engl J Med, 1990.
11. Sigal LH. Am J Med, 1990.
12. Dinerman H et al. Ann Intern Med, 1992.

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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