By:Elizabeth Williams

Orphan Disease

An orphan disease is any disease that affects a small percentage of the population.


  • ADM
  • Childhood dermatomyositis
  • Idiopathic inflammatory myopathy
  • IIM
  • Polymyositis

General Description

Dermatomyositis is a progressive connective tissue disorder characterized by inflammatory and degenerative changes of the muscles and skin. Skin abnormalities associated with dermatomyositis often include a distinctive reddish-purple rash (heliotrope rash) on the upper eyelids, across the cheeks and bridge of the nose in a "butterfly" distribution, the forehead, or additional skin regions; scaling and degenerative (atrophic) changes of affected skin on the extending surfaces of the knuckles, elbows, knees, and/or other regions (Gottron's sign); an abnormal accumulation of fluid (edema) in body tissues surrounding the eyes; and/or other features.

Signs & Symptoms

  • muscle weakness
  • muscles may be stiff, sore, and/or tender
  • degeneration and muscle wasting
  • awkward manner of walking
  • gradual inability to perform certain tasks: such as lifting the arms, climbing steps, or dressing
  • inability to raise the head from the pillow when lying down
  • difficulties swallowing (dysphagia)
  • distinctive reddish-purple or lilac (i.e., heliotrope) rash


The specific underlying cause or causes of dermatomyositis remain unknown. However, evidence suggests that genetic, immune, and environmental factors play some role.

Affected Populations

  • Infancy through approximately age 80
  • More commonly between 40 to 60 years
  • Symptoms usually appear between the ages of five to 15 years
  • Approximately three in 1,000,000 children are affected by juvenile dermatomyositis
  • Females are affected by Dermatomyositis twice as often as males.

Related Disorders

  • Polymyositis
  • Inclusion Body Myositis
  • Scleroderma
  • Systemic lupus erythematosus (SLE)


Dermatomyositis may be diagnosed based upon a detailed patient history, thorough clinical examination, detection of characteristic physical findings, and certain specialized tests.

Standard Therapies

  • The treatment of dermatomyositis is directed toward the specific symptoms that are apparent in each individual
  • Affected children may initially require high dose therapy with prednisone, which often results in a return of muscle enzyme levels toward normal levels within about one to two weeks
  • As with adults, decreased muscle inflammation and improved muscle strength typically follow.
  • Therapy with other immunosuppressive drugs, such as azathioprine, methotrexate, cyclophosphamide, chlorambucil, or cyclosporine, may be beneficial for some affected individuals who have an insufficient response to corticosteroid therapy alone, dose-limiting adverse effects, or frequent relapses.

Supporting Organizations

  • American Autoimmune &Related Diseases
  • Myositis Association
  • Arthritis Foundation
  • Muscular Dystrophy Association