Can Lyme Disease Cause Myositis?

Yes—Lyme disease can rarely cause myositis, a condition involving inflammation of muscle tissue.

In some cases, muscle swelling or eye symptoms may be the first sign of infection.

This condition—sometimes referred to as Lyme myositis—is an uncommon but important manifestation of infection.

One form, called orbital myositis, affects the muscles around the eye and may cause swelling or double vision.

Myositis refers to inflammation of muscle, which may cause pain, swelling, or weakness.

For a broader overview, see Lyme disease symptoms guide.

What Is Lyme Myositis?

Lyme myositis occurs when infection with Borrelia leads to inflammation in muscle tissue.

Orbital myositis is a specific form involving the eye muscles and is typically associated with systemic diseases such as Graves’ disease or hematologic conditions.

When caused by Lyme disease, it is considered a rare manifestation.

Symptoms of Lyme-Related Myositis

• Muscle swelling
• Pain in affected muscles
• Eye swelling or discomfort (orbital involvement)
• Double vision (diplopia)
• Fatigue or systemic symptoms

Recognizing this pattern is important, as these symptoms may be mistaken for autoimmune or inflammatory conditions.

Case: Orbital Myositis From Lyme Disease

This report describes two patients with orbital myositis linked to Lyme disease.

In both cases, MRI confirmed inflammation of the eye muscles.

Patient 1: 68-year-old woman

The patient experienced recurrent episodes of right orbital swelling and pain lasting 2 to 4 weeks.

Episodes resolved spontaneously or with anti-inflammatory medications.

Lyme disease was suspected due to her history of tick exposure, erythema migrans rash, and arthralgia.

Testing confirmed Lyme disease, and treatment with doxycycline led to resolution of symptoms within 3 weeks.

Patient 2: 13-year-old girl

The adolescent presented with unilateral orbital swelling, exophthalmos, and double vision.

MRI showed inflammation of the extraocular muscles.

She had a recent tick bite followed by an erythema migrans rash.

Lyme disease testing was positive, and treatment with doxycycline led to symptom resolution within one month.

This presentation is consistent with findings described by Sauer et al. (https://pubmed.ncbi.nlm.nih.gov/22567470/), who reported orbital myositis as a rare manifestation of Lyme borreliosis.

Why Lyme Myositis Can Be Missed

• Symptoms resemble autoimmune or inflammatory muscle disorders
• Orbital myositis is usually linked to non-infectious causes
• Tick exposure or rash may not be recognized

This can delay diagnosis, particularly when Lyme disease is not initially suspected.

How Common Is Myositis in Lyme Disease?

Myositis is an uncommon manifestation of Lyme disease.

Most cases involve joints, nerves, or skin rather than muscle inflammation.

Orbital involvement is especially rare but likely underdiagnosed.

FAQ: Lyme Disease and Myositis

Can Lyme disease cause myositis?
Yes. Although uncommon, Lyme disease can cause inflammation of muscle tissue.

What is orbital myositis?
Orbital myositis is inflammation of the muscles around the eye, which may cause swelling, pain, or double vision.

What causes orbital myositis?
It is usually linked to autoimmune conditions but can rarely be caused by infections such as Lyme disease.

Is Lyme myositis common?
No. It is a rare manifestation of Lyme disease.

Can Lyme-related myositis be treated?
Yes. Most cases improve with appropriate antibiotic therapy.

Clinical Takeaway

Lyme disease can rarely cause muscle inflammation, including orbital myositis affecting the eye muscles.

Unexplained muscle swelling—especially with a history of tick exposure or rash—should prompt consideration of Lyme disease.

Early diagnosis and treatment can lead to resolution of symptoms.

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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