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Bulbar Weakness and Rash

By Joshua Sonnen, MD

Nov 30, 2023

Dermatomyositis with treatment effect

Clinical History

  • 68-year-old woman with dysphagia, dysarthria, facial muscle weakness and rash
  • Past medical history – breast cancer
  • Medications –hydroxychloroquine and IVIG (at time of biopsy)


What is the process?

A. Dermatomyositis with treatment effect

B. Amyotrophic dermatomyositis

C. Anti-synthetase syndrome

D. MxA-related myopathy



Correct answer: A.Dermatomyositis with treatment effect

Dermatomyositis (DM) with treatment effect

  • MHC class I and C5b-9 positivity support inflammatory myopathy
  • CD3 + infiltrate suppressed by immunomodulatory therapy
  • Perifascicular alkaline phosphatase and MxA (surrogate for interferon-β) positivity in myofibers in DM even w/o perifascicular atrophy


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