Juvenile Dermatomyositis - Symptoms, Diagnosis, and Management

Introduction

An immune system is a group of cells that protect the body from potential infections. Dermatomyositis is a group of autoimmune diseases that cause inflammation in muscles. In patients with juvenile dermatomyositis, the body attacks its tissue, causing inflammation and tissue damage.

What Is Juvenile Dermatomyositis?

Juvenile dermatomyositis is an autoimmune condition in which children's muscles, skin, and blood vessels are affected. The body’s immune system mistakenly attacks healthy muscles, skin, and blood vessels, seeing them as invaders. As a result, the presenting symptoms are muscle weakness and skin rashes due to an inflammatory process caused by a hyperactive immune system.

What Is the Incidence of Juvenile Dermatomyositis?

• It is a rare condition.

• Girls are more affected than boys.

• Disease development is expected for children between the ages of 2 to 15 and adults between 40 to 50 years.

• The disease can affect any age and ethnic group.

What Are the Causes of Juvenile Dermatomyositis?

The body’s immune system continues to fight even when trigger factors are removed, resulting in the attacking of healthy cells. The exact etiology is unknown. However, studies suggest the cause of the body’s autoimmune response to environmental factors (viruses), genetics, or having a hyperactive immune system.

What Are the Symptoms of Juvenile Dermatomyositis?

The symptoms result from inflammation in small blood vessels and muscle cells. The severity of symptoms varies from mild to severe.

• Muscle weakness is gradual and debilitating. The large neck, shoulders, trunk, back, or hip muscles are commonly affected. This can cause difficulty in getting in the car and brushing hair. The muscle weakness is symmetrical.

• Mild pain in muscles or tenderness.

• Skin rash that is violet or dusky red. A patchy, bluish-purple-colored rash is the first sign of disease. The rashes appear on the face, eyelids, cheeks, chest wall, knees, back of the elbow, and nails. The rashes can develop into ulcers.

• Polymyositis and focal myositis can occur in children.

• Raised bumps on knuckles. They can be misdiagnosed as eczema.

• The difficulty arises in everyday activities like climbing stairs, getting off a chair, standing up, riding a bicycle, turning over in bed, getting dressed, or lifting the head.

• Frequent fall.

• Weak voice (dysphonia).

• Difficulty swallowing (dysphagia).

• Fever.

• Contracture of muscles.

• Sore, stiff, and swollen joints.

• Fatigue and loss of appetite.

• Loss of interest in regular activities.

• Weight loss.

• Severe abdominal pain caused by ulcers in the digestive system.

• Hardened lumps are caused by calcium deposition underneath the skin (calcinosis).

• Intestinal tears.

• Inflammation and thickening of the small airway in the lungs can cause lung problems.

The disease symptoms cause the child to avoid normal activities, resulting in laziness.

How Is Juvenile Dermatomyositis Diagnosed?

Diagnosis becomes difficult for a rare disease.

• Medical history.

• Physical examination to look for rashes in the skin.

• Presence of proximal muscle weakness.

• Blood tests detect elevated muscle enzymes caused by inflammation, including CPK (creatinine phosphokinase), aldolase, SGOT (serum glutamic-oxaloacetic transaminase), SGPT (serum glutamic pyruvic transaminase), and LDH (lactate dehydrogenase).

• Antibodies are detected in the blood, responsible for muscle weakness, and guide treatment, prognosis, and see other organ involvement.

• Magnetic resonance imaging (MRI) is used to detect mild muscle inflammation and swelling in early disease and determine the inflamed muscle's location. The test utilizes a magnetic field and radio waves to produce a radiographic image in the computer. MRI is a preferred type of investigation due to its sensitivity and ability to view patches of muscle inflammation as a whole.

• Muscle or skin biopsy is a technique in which a small piece of tissue is examined under a microscope. On examination, inflammatory muscles appear, surrounding and damaging blood vessels in the skin and muscle. They help in the differential diagnosis of muscular dystrophy or infection.

• In a nail fold capillaroscopy, a patient with juvenile dermatomyositis presents with abnormal swelling and distortion of blood vessels around nails indicative of active disease. Doctors can examine the nail bed with a lighted magnifying tool.

How to Treat Juvenile Dermatomyositis?

Treatment is dependent on the severity of the disease. The main aim of treatment is to control inflammation, prevent tissue damage, relieve pain, improve muscle strength, and improve quality of life.

Medications:

1. Corticosteroids (Prednisone) are the first line of treatment. The drug slows the body’s autoimmune response by limiting the production of antibodies and reducing skin and muscle inflammation. They may also reduce pain and improve muscle strength. The duration of treatment with steroids depends on disease severity. The steroids are given orally or intravenously and are gradually weaned by tapering. Prolonged use of steroids causes weakening of bone, cataracts, and upset stomach.

2. Immunosuppressants (Methotrexate, Azathioprine, and Cyclosporine) prevent overactivity of the immune system by suppressing their response. They are used alone or as an adjunct with steroids; prolonged use of the drug results in nausea, damage to organs, and increased susceptibility to infections. Methotrexate is a commonly used adjunct to steroids.

3. Intravenous immunoglobulin suppresses the immune system by blocking antibodies that attack muscle and skin. The drug causes the adverse effects of backache, headache, and fever. The dose must be repeated every three to four weeks.

4. Hydroxychloroquine, Rituximab, and anti-TNF (Etanercept, Adalimumab, and Infliximab) can be effectively used. The drugs are used in severe diseases as an adjunct to other medications. In rare instances, prolonged use of Hydroxychloroquine can cause color vision in children.

5. Biological agents can be used for juvenile dermatomyositis. However, the treatment is expensive, and there is a risk of developing infections.

Other Modes of Treatment:

1. Skin Protection - Patients can prevent muscle disease and control skin rashes by protecting themselves from ultraviolet A and B lights. The protection is achieved through sunscreen, sunblock, wide-brimmed hats, and photoprotective clothing.

2. Physical Therapy - Physical activity is essential to recover from juvenile dermatomyositis. Patients must do exercises to improve strength and flexibility. In addition, the therapy helps prevent muscle wasting.

3. Speech Therapy - Speech therapy can overcome the limitations in patients with weak swallowing muscles. As chewing and swallowing become difficult, dieticians must advise food that is easier to eat.

What Is the Prognosis for Juvenile Dermatomyositis?

There is an excellent response to treatment for this disease. Most patients show a complete recovery, but few may not improve. Patients with longer disease courses are at risk for muscle weakness, stiffness, calcinosis, or cardiopulmonary disease.

Conclusion

Juvenile dermatomyositis is a rare, long-term disease affecting skin, muscle, and blood vessels. Unlike dermatomyositis in adults, this juvenile type is not prone to develop as malignancy. Various treatment modalities are available to manage the disease. Corticosteroids, Hydroxychloroquine, and targeted biotherapies such as Rituximab are used as medications. Physical therapy helps to increase muscle strength by preventing joint contractions. Most patients show good recovery.