Pediatric Dermatolyositis - Causes, Symptoms and Management

Introduction

Autoimmune diseases are those where the immune system attacks healthy cells and tissues, causing inflammation and damage in the body. Depending on the cells attacked, the disease condition varies. When the immune system attacks the joints, it causes a bone disease called rheumatoid arthritis. Pediatric dermatomyositis is one such autoimmune condition that affects children.

What Is Pediatric Dermatomyositis?

Pediatric dermatomyositis is a rare autoimmune disease that mainly affects children and causes inflammation of the muscles, skin, and blood vessels. The immune system attacks the cells and tissues of the muscle and the skin, leading to muscle weakness and skin rashes. Affected children usually present symptoms of the condition between five and ten years of age, although the condition may affect children as young as two and as old as sixteen years of age.

What Are the Causes of Pediatric Dermatomyositis?

The exact cause and pathogenesis of pediatric dermatomyositis are not known. Studies suggest that the autoimmune response by the body could be triggered by the presence of multiple factors, such as genetic factors (for example, a family member with autoimmune diseases) or environmental factors (for example, a viral infection that triggers an immune system attack), that may contribute to the development of pediatric dermatomyositis.

What Are the Symptoms of Pediatric Dermatomyositis?

Children may present with different symptoms depending on the age of the onset of the condition. The symptoms may progress over a period of time or appear with no warning and affect very severely. Some of the commonly presented symptoms are as follows:

• Skin - Inflammation of the skin cells as an autoimmune reaction may present in the form of:

  • Rashes may be seen on eyelids.

  • Rashes or elevated lumps on knuckles.

  • Finger joints may also be affected by patchy rashes.

  • Rash on the joints, such as the elbows, knees, and ankles.

  • Calcinosis (a condition where calcium deposits under the skin).

• Muscle - Inflammation of the muscle cells as an autoimmune reaction may present in the form of:

  • Weakness, particularly affecting the muscles of the neck, hips, and shoulders.

  • Fatigue may be mild or severe in nature.

  • Daily movements may feel tedious.

  • Muscle pain and soreness.

  • Muscle atrophy (thinning away of the muscle tissue).

  • Dysphagia (where the muscles involved in swallowing fail to function well and cause difficulty in swallowing).

  • Contracted positioning or paralysis of some muscles.

• Blood Vessel - The skin may appear purple or reddish due to the inflammation of cells in the underlying blood vessels.

• Other Symptoms Include:

  • Joint pain and inflammation.

  • The mouth may present with ulcers.

  • Difficulty in breathing due to narrowing of the airway due to inflammation.

  • Ulcers in the stomach and intestines.

  • Loss of weight.

  • Feeling sick (malaise) or having a fever.

How to Diagnose Pediatric Dermatomyositis?

Skin rashes and muscle weakness may be misdiagnosed as some other condition in children. Proper physical examination, blood tests, imaging tests, and a biopsy can help confirm the diagnosis of the disease condition.

• Physical Examination- Skin is examined for the presence of colored (blue, purple reddish) rashes. Muscle strength is tested mainly with manual muscle testing (MMT), where the pressure with which a child resists certain muscle movements by the therapist is observed.

• Blood Tests- Blood tests can detect the presence of certain antibodies, such as anti-Jo-1 and anti-Mi-2, which are commonly associated with dermatomyositis. An increase in muscle enzymes such as creatine kinase indicates muscle damage.

• Imaging Tests- Magnetic resonance imaging (MRI), where the muscle tissue is examined for inflammation. Smaller parts of inflammation can also be detected from magnetic resonance imaging tests, making it beneficial for early diagnosis of the disease condition.

• Electromyogram (EMG)- It is a test done to detect damage to any muscle in the body by measuring the electrical activity of the muscle. This test can also help detect nerve damage.

• Biopsy- A procedure where a small tissue sample is excised for observation under the microscope for diagnostic purposes.

  • Skin Biopsy - Examination of the skin tissue sample under the microscope will show the presence of inflammatory cells around the small blood vessels of the skin.

  • Muscle Biopsy - Examination of the muscle tissue sample under the microscope will show the presence of inflammatory cells indicative of muscle tissue damage.

• Capillaroscopy of Nail Bed - It is a non-invasive imaging technique where the nail beds are examined under a magnifying glass or tool for the presence of any swelling or abnormalities of the nail bed capillaries.

How to Treat Pediatric Dermatomyositis?

The treatment modalities aim to reduce pain and inflammation, prevent the progression of the disease, and subsequently improve the quality of life for the child with improvements in bodily movements and functions. The treatment approach varies depending on the age of the child, the onset, and the severity of the disease condition.

• Medications - Corticosteroids (for example, Prednisolone) help reduce inflammation by acting on the overactive immune system.

  • Treatment with a high dose of Glucocorticoids is initiated daily in single or divided doses and reduced gradually once the symptoms start to improve.

  • Corticosteroids (for example, Prednisolone) or glucocorticoids (for example, Methylprednisolone) may be administered intravenously depending on the severity of the condition. A visible improvement in the child may be noticed only after a few weeks, and in some cases, it may take months for the same.

  • Prolonged use of corticosteroids have serious side effects that may affect the health of the bone and eye, and body; hence close monitoring is necessary.

  • Immunosuppressive drugs (for example, Methotrexate) may be given along with corticosteroid drugs to control the immune system and reduce inflammation.

  • Immunoglobulin-G (IgG) may be given intravenously when other treatments fail. Immunoglobulin-G helps by preventing the immune system attack on the body. It is accepted better as immunoglobulin-G are antibodies derived from donated blood plasma.

• Physical Therapy - It is advised to improve muscle strength, flexibility, and movements of the body. Regular daily exercises can help prevent muscle contractions and thinning of the muscle.

• Protection of the Skin - The presence of rashes makes the skin more prone to sun damage. Use of sun-protective clothing, gear, and sunscreens with good SPF (sun protection factor) is recommended while stepping out during the day for children with dermatomyositis.

• Speech Therapy - Exercises to strengthen the weakened muscles in the vocal area to improve swallowing and speech.

Conclusion

With appropriate treatment measures after a proper diagnosis, children do recover and are free from the symptoms for a prolonged period. However, relapse may occur, or in some cases, the child may continue to have the disease condition regardless of the treatment measures. Proper monitoring of the child, along with a healthy diet and lifestyle practices (proper sleep and exercise), can help the child have a good quality of life.