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Juvenile Myositis

What is juvenile dermatomyositis?


Juvenile dermatomyositis is a rare systemic autoimmune disorder that causes inflammation in the small blood vessels of the entire body, especially those located in the muscles and skin. The muscle inflammation (myositis) leads to muscle weakness and pain, while the skin inflammation (dermatitis) leads to rashes in the face, knuckles and other joints.


  • All patients with dermatomyositis have a rash. 

    • Rash is pink, red or shows flesh-colored bumps over the joints.

    • Purple discoloration of the eyelids

    • Redness over the cheeks and nose 

    • Other rashes, such as redness at the nail folds

  • Muscle weakness

    • Progressive inflammation of the proximal muscles (muscles closest to the center of the body including the hip, neck, shoulders and abdomen)

    • Severity ranges from minor to the inability to climb stairs, stand up, walk or get dressed, decreased play activity, tiredness 

    • Severe neck weakness can lead to trouble swallowing, voice changes, difficulty breathing 

    • Muscles can be tender to touch

  • Photosensitivity, meaning rashes are worsened by exposure to the sun. 

  • Joint pain or stiffness 

Diagnosing juvenile dermatomyositis


JDM can usually be diagnosed based upon clinical symptoms, physical exam (classic rash), and lab tests (increased muscle enzymes). Because other autoimmune and genetic diseases can cause muscle weakness, your doctor may do additional testing to confirm the diagnosis of JDM such as an MRI, muscle biopsy or EMG.


In most cases, JDM is treated with a combination of medications. Patients can expect to be on medications to treat JDM for at least two years.

For more information, visit the American College of Rheumatology and the Myositis Association.