Lyme Disease Mimics Dermatomyositis in Elderly Woman
Rash and muscle weakness suggested dermatomyositis
Target-shaped lesions later pointed to Lyme disease
Antibiotic treatment led to recovery
Lyme disease can occasionally mimic autoimmune diseases, including dermatomyositis. Symptoms such as fatigue, muscle weakness, weight loss, and characteristic skin rashes may initially suggest an autoimmune disorder rather than a tick-borne infection.
The clinical presentation was consistent with dermatomyositis (DM). “A 76-year-old female presented with fatigue, malaise, weight loss and progressive proximal muscle weakness after a flare-up of shoulder arthritis,” writes Novitch, a medical student at the Medical College of Wisconsin.
Why Dermatomyositis Was Suspected
The physical findings were consistent with DM. “She had a heliotrope rash and a ‘Shawl sign,’ in addition to generalized cutaneous erythema with edema,” writes Novitch.
A heliotrope rash is a violet or bluish-purple rash that develops on areas of the skin. “A widely distributed erythema of the upper neck, extending to the upper back and upper shoulders indicating a ‘Shawl sign’ was noted,” Novitch states.
Common dermatomyositis symptoms include muscle weakness, fatigue, weight loss, and characteristic skin rashes. In this case, Lyme disease initially appeared to fit that diagnosis.
Lyme Disease Confirmed
The doctors prescribed antibiotics for Lyme disease based on clinical judgment. The woman was prescribed an empiric dose of IV Rocephin but began to deteriorate.
“The patient appeared toxic, became hypotensive and developed high-grade fever,” writes Novitch. She was transferred to the intensive care unit (ICU) for close monitoring.
The doctor’s clinical judgment of Lyme disease proved to be correct.
“While in ICU, two target-shaped lesions were noted on her left scapula, highly suggestive of LD-related EM; they were not previously reported or observed,” writes Novitch.
Follow-up serologic tests confirmed the diagnosis of Lyme disease.
The patient recovered with a combination of 5 days of IV doxycycline combined with 5 days of IV Rocephin followed by two weeks of oral doxycycline.
“Her DM-like presentation showed an effective response to antimicrobial treatment, and therefore, required no steroids or immunosuppressants,” writes Novitch.
Lyme Disease as an Autoimmune Mimic
Novitch and colleagues point out that “LD could be a great mimicker of other autoimmune diseases like DM.”
This case illustrates how Lyme disease can occasionally resemble autoimmune disorders with muscle weakness, fatigue, rash, and systemic symptoms. Recognizing Lyme disease in the differential diagnosis may help avoid unnecessary immunosuppressive treatment and lead to appropriate antibiotic therapy.
Frequently Asked Questions
Can Lyme disease be mistaken for dermatomyositis?
Yes. Lyme disease can occasionally resemble dermatomyositis with muscle weakness, fatigue, rash, and systemic symptoms. Careful evaluation may help distinguish between the two conditions.
Can Lyme disease mimic an autoimmune disease?
Yes. Lyme disease has been reported to mimic several autoimmune disorders, making diagnosis challenging in some patients.
What symptoms made this case resemble dermatomyositis?
The patient had fatigue, weight loss, proximal muscle weakness, a heliotrope rash, and a Shawl sign, all findings that can be seen in dermatomyositis.
Clinical Takeaway
Lyme disease should remain part of the differential diagnosis when patients present with rash, muscle weakness, fatigue, and features suggestive of autoimmune disease.
In this case, recognizing Lyme disease prevented the need for long-term immunosuppressive therapy and led to successful treatment with antibiotics.
Related Articles
Learn more about whether Lyme disease can mimic autoimmune disease, how Lyme disease can be misdiagnosed as shingles, and whether Lyme disease may be associated with Guillain-Barre syndrome.
References
- Novitch M, Wahab A, Kakarala R, Mukerji R. The Emergence of a Forgotten Entity: Dermatomyositis-like Presentation of Lyme Disease in Rural Wisconsin. Cureus. 2018;10(5):e2608.
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
