Juvenile Myositis (JM) is found in children under the age of 18 and affects 3,000 to 5,000 children in the United States. Juvenile dermatomyositis, or JDM, is a disease marked by muscle weakness and skin rash. The other form of myositis that can occur in children – juvenile polymyositis – is extremely rare.
The first sign of JM is usually a skin rash. The rash may be red and patchy, like dry skin; a red or purplish color on the eyelids or cheeks that may look more like allergies; or both. Children with juvenile polymyositis do not experience skin symptoms.
JM patients can have weak muscles at the same time they see the skin rash, or the weak muscles may come after the rash over days, weeks or months. The weaker muscles are usually closer to the body (for example, neck, shoulders, back, and stomach), and you may notice your child having trouble climbing or standing from a seated position. The skin rash and weak muscles are caused by inflammation or swelling in the blood vessels under the skin and in the muscles.
Other signs may include falling, weaker voice (dysphonia), or problems swallowing (dysphagia). About half of the children with JM have pain in their muscles.
Some children may have calcinosis, hardened lumps or sheets of calcium under the skin, or contractures, in which the muscle shortens and causes the joint to stay bent. Exercising the muscles can prevent contractures.
Signs and symptoms
- Visible, reddish-purple rash over the eyelids or joints
- General tiredness
- Moodiness or irritability
- Complaints of tummy aches
- Trouble climbing stairs or onto a bus; standing from a seated position; getting dressed
- Difficulty reaching up, like to shampoo or comb hair
- Trouble lifting the head
- Swelling or redness in the skin around the fingernails
- Characteristic reddish-purple rashes of JM—Gottron's papules (bumps found over the knuckles, elbows and knees) and heliotrope rash (purplish rash around the eyes)
- Gradual muscle weakness, most often of those closest to the body like neck, stomach, upper arms and legs
- Hardened lumps or sheets of calcium (calcinosis) under the skin
- Trouble swallowing (dysphagia)
- Hoarse-sounding voice
- Stomach problems
Updated March 2012