Juvenile Myositis (JM) is found in children under the age of 18 and affects two to four children per million. The most frequent form of juvenile myositis is juvenile dermatomyositis (JDM), in which children experience marked muscle weakness and skin rash. Juvenile polymyositis can also occur in children, but it is extremely rare. There is no known cause or cure for juvenile myositis. However, there are treatments that can successfully manage the symptoms.
Juvenile Myositis Signs and Symptoms
The following are common signs and symptoms for juvenile dermatomyositis and polymyositis:
- 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, or getting dressed
- Difficulty reaching up, like to shampoo or comb hair
- Trouble lifting the head
- Swelling or redness in the skin around the fingernails
- Gradual muscle weakness, most often those closest to the body such as neck, stomach, upper arms, and legs
- Hardened lumps or sheets of calcium (calcinosis) under the skin
- Trouble swallowing (dysphagia)
- Hoarse-sounding voice
As is the case for dermatomyositis, the first sign of JDM 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. Gottron’s papules, rashes, or lesions over the knuckles, elbows, and knees, and heliotrope rash, a purplish rash around the eyes, are common.
Children with juvenile polymyositis do not experience skin symptoms.
JDM patients can have weak muscles at the same time they see the skin rash, or the weakening muscles may occur after the rash over days, weeks, or months. The weaker muscles are usually those closer to the body, in the neck, shoulders, back, and torso. The child may have 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 JDM have pain in their muscles. Some children may also develop calcinosis, in which hardened lumps or sheets of calcium develop under the skin. Contractures can also occur, where the muscle becomes shortened and causes the joint to stay bent. Exercising the muscles and joint range of motion can prevent contractures.
If your child is experiencing any of these juvenile myositis symptoms, we encourage you to talk to your doctor to begin the diagnosis process. Since juvenile myositis is a rare disease, not all physicians are familiar with the signs and symptoms. If you are struggling to find an accurate diagnosis, visiting a specialist can help.