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dermatomyositis

dermatomyositis

introduction

  • a connective-tissue disease related to polymyositis (PM) that is characterized by inflammation of the muscles and the skin
  • may also affect the joints, the esophagus, the lungs, and, less commonly, the heart
  • ~100-200 cases per million
  • more common in women
  • juvenile form is similar
  • is often associated with Anti-Jo1 antibodies, Anti-signal recognition particle antibodies (anti-SRP) and Anti-Mi-2 antibodies
  • often associated with underlying cancers, in particular, ovarian tumours, lung cancer, and pancreatic cancer

clinical features

  • presents as a proximal symmetrical muscle weakness with vasculitis affecting the skin, muscles and internal organs
  • many find it hard to raise their arms to comb their hair or walk up the stairs due to the proximal muscle weakness
  • other possible features:
    • calcinosis can occur in the skin, joints and tissues
    • Gottron lesions
      • scaly erythematous eruptions or red patches overlying the knuckles, elbows, and knees are a characteristic feature
    • periungual telangiectasiae
    • heliotropic (purple) rash over the upper eyelids
    • Shawl (or V-) sign is a diffuse, flat, erythematous lesion over the back and shoulders or in a “V” over the posterior neck and back or neck and upper chest, which worsens with UV light.
      • erythroderma is not a flat, erythematous lesion similar to the shawl sign but located in other areas, such as the malar region and the forehead.
    • mechanic's hands (also in PM)
      • rough, cracked skin at the tips and lateral aspects of the fingers forming irregular dirty-appearing lines that resemble those seen in a labourer
    • psoriaform changes in the scalp
    • centripetal flagellate erythema comprises linear, violaceous streaks on the trunk (possibly caused by itching pruritic skin)
    • calcinosis cutis (deposition of calcium in the skin) is usually seen in juvenile dermatomyositis, not adult dermatomyositis
    • dysphagia occurs in a third
    • dystrophic calcifications in the muscles on XR

diagnosis

Rx

dermatomyositis.txt · Last modified: 2013/10/21 04:36 by gary1