What is Juvenile
Myositis?

Juvenile myositis is a rare autoimmune disease in which the body’s immune system attacks its own cells and tissues. Your doctor may refer to juvenile myositis as juvenile dermatomyositis or JDM. Juvenile dermatomyositis is the most common form of the disease.


Juvenile myositis affects each child differently as the immune system typically attacks muscle and skin, resulting in significant and sometimes severe weakness and persistent rash. The exact cause of JM is unknown. Current treatments are imperfect yet have reduced the mortality rate to less than 3%.

Two young girls hold a Cure JM ballon.
Approximately 2 to 4 children per million are diagnosed with JM yearly in the U.S.
The average age of onset for JDM is between six to seven years old; 25% are age four or younger
JDM affects girls twice as often as it affects boys
Doctor and young juvenile myositis patient.

What is Juvenile Myositis?

Juvenile myositis, including juvenile dermatomyositis and juvenile polymyositis, is a group of rare and life-threatening autoimmune diseases, in which the body’s immune system attacks its

Juvenile Myositis 101

A world-renowned pediatric rheumatologist and immunologist tells us what juvenile dermatomyositis (JDM) is, how it is diagnosed, and how it is treated.

Myositis and You Book Cover

Myositis and You

This comprehensive guide features over 450 pages with contributions from over 80 experts and medical professionals.

Receive a free digital copy when you join Cure JM here.

  • Learn what juvenile myositis is and how to explain it to children
  • Understand the symptoms of JM, tests used to diagnose it, and how to find medical help
  • Find strategies to help your child adjust to physical limitations and to cope with JM as a family
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