The Emergence of a Forgotten Entity: Dermatomyositis-like Presentation of Lyme Disease in Rural Wisconsin.

Dermatomyositis (DM) is one of the rare clinical manifestations of tickborne-related autoimmune presentations; we report an uncommon case of Borrelia-related DM-like presentation from rural Wisconsin. A 76-year-old female presented with fatigue, malaise, weight loss and progressive proximal muscle weakness after a flare-up of shoulder arthritis. She had a heliotrope rash and a Shawl sign in addition to generalized cutaneous erythema with edema. There was no history of tick bite, Lyme disease (LD) or DM. The physical exam revealed erythema migrans (EM) and DM-like musculocutaneous findings. Enzyme-linked immunosorbent assay and western blot were positive for LD. The patient received intravenous ceftriaxone and doxycycline for five days, leading to the resolution of EM lesions and improvement in her muscle weakness. In addition, DM-like features resolved with antiborrelial treatment and required no steroids or immunosuppressants. Workup including electromyography, skin or muscle biopsy could not be performed as the patient improved clinically. At six months post-treatment, she remained in remission.