What is juvenile dermatomyositis?

Juvenile dermatomyositis (JDM) is a rare disease that causes muscle inflammation and a skin rash. It's different from other muscle diseases because it also causes skin problems. Symptoms often first appear in children between ages 5 and 10. Children with JDM have weak muscles around the neck, shoulders, and hips. They also have a skin rash around certain areas, such as the eyelids, knuckles, and finger joints.

What causes juvenile dermatomyositis?

The exact cause is not yet known. But it may be linked to problems with the immune system that cause inflammation in the muscle cells and blood vessels.

What are the symptoms of juvenile dermatomyositis?

JDM symptoms often appear slowly over time. In some cases, they may happen more quickly or severely. Each child’s symptoms may vary. The most common symptoms include:

• Fever

• Rash around the eyelids, knuckles, or finger joints

• Rash on the elbows, knees, and ankles

• Muscle weakness

• Lack of energy (fatigue)

• Ill feeling (malaise)

• Muscle pain and soreness

• Irritable mood

• Trouble swallowing

• Weight loss, due to trouble swallowing

• Joint pain and inflammation

• Calcium deposits under the skin (calcinosis)

• Mouth ulcers

• Muscles wasting away (muscle atrophy)

• Some muscles may become paralyzed in a contracted position

• Abnormal swelling and distortion of the blood vessels around the nails

These symptoms can seem like other health conditions. Make sure your child sees their healthcare provider for a diagnosis.

How is juvenile dermatomyositis diagnosed?

Your child's healthcare provider will ask about your child's health history and do a physical exam. Your child may also have tests, such as:

• Blood tests. These tests are used to check for antibodies, muscle enzymes, and signs of inflammation.

• Electromyogram (EMG). This is an electrical test that may be done to find nerve or muscle damage.

• MRI. This test uses large magnets and a computer to look for inflammation in the body.

• Muscle and skin biopsy. Tiny tissue samples are removed and examined under a microscope.

• Nailfold capillaroscopy. The nail beds are examined using a lighted magnifying tool. Abnormal swelling and distortion of nail beds suggests active disease.

How is juvenile dermatomyositis treated?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

There is no known cure for JDM. But the symptoms can be managed. The disease may go into remission. This means the symptoms will go away. Treatments may include:

• Medicines. These are used to treat inflammation and skin symptoms.

• Physical and occupational therapy. This can help to improve muscle function and strength.

• An exercise program. This can also help improve muscle function and strength.

• Sunscreen. Using sunscreen helps prevent more irritation or damage to the skin.

• Nutrition. A healthy diet will help support the body during the disease.

• Supplements and vitamins

Talk with your child’s healthcare provider about the risks, benefits, and possible side effects of all medicines.

What are possible complications of juvenile dermatomyositis?

Many children will recover from JDM without any lasting problems. Some children may have trouble moving because of shortening of the joints (contractures). Some children will develop calcifications in the skin that lead to visible lesions, pain, or decreased range of motion of the joints. Other children may have ongoing (chronic) symptoms. These may include pain, muscle weakness, and delayed growth. There may be damage to bones, joints, lungs, and other internal organs.

Helping your child live with juvenile dermatomyositis

Juvenile dermatomyositis can make it hard for a child to take part in school and other activities. Work with your child’s school to help teachers and caregivers understand your child’s limits. A healthy lifestyle can help improve your child’s quality of life. This includes a good diet, exercise, and rest. Watch for signs of anxiety or depression and get counseling services if needed. Check social media activity and be on the lookout for any signs of bullying. Take action if needed. A support group may help your child feel less alone or different.

When should I call my child’s healthcare provider?

Tell the healthcare provider if your child's symptoms get worse or there are new physical or emotional symptoms.

Key points about juvenile dermatomyositis

• Juvenile dermatomyositis (JDM) is a rare disease that causes muscle inflammation and a skin rash.

• Symptoms often first appear in children between ages 5 and 10.

• Symptoms include fever, rash, muscle weakness and pain, and calcium deposits under the skin.

• The condition also causes a rash around the eyelids, knuckles, or finger joints. A rash may also occur on the elbows, knees, and ankles.

• Some children may have a complete remission of the disease. Others may have chronic symptoms that continue.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• Know the reason for the visit and what you want to happen.

• Before your visit, write down questions you want answered.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new directions your provider gives you for your child.

• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

• Ask if your child’s condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if your child does not take the medicine or have the test or procedure.

• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.