Dermatomyositis

Dermatomyositis is a disorder which frequently involves the muscle and skin manifesting as weakness or stiffness and purple to red skin discoloration. It may involve other organs like the lungs and esophagus. ^{[1] [2]}

Epidemiology

9.63 cases per million are recorded. Virtually any age can be affected. Two peaks are known. The first is during childhood usually during 5-10 years of age. The second peak is at adulthood around 50 years of age. Females are shown to have the condition more. ^[1]

Causes

The exact cause remains unknown. Genes are implicated to have an association in the development of the disease. Aberrations in immune system are common among patients. Viral infections are thought to be triggers in some cases. Among the organisms suspected are coxsackievirus, echovirus, HIV and Toxoplasma. Certain drugs are also thought to be likely causes such as penicillamine, hydroxyurea and statins. Some reports silicone breast implants or collagen injection as probable triggers although these are yet to be substantiated. ^[1]

Signs and Symptoms

One of the early symptoms is skin lesion. Commonly, it is a purple or red discoloration of the skin seen on typical locations like eyelids, knuckles, elbows or knees. After weeks or up to years, muscle involvement is observed. This is often noted as weakness of the proximal group of muscles. Patients may complain of climbing stairs, difficulty getting out of a chair or reaching for objects situated above them.  The disease can involve other organs so that some patients may have arthritis, gastrointestinal ulcers, difficulty of swallowing and lung problems. Fatigue, fever and weight loss are also among the nonspecific symptoms of the disease. ^[3]

Diagnosis

After getting the patient’s history, the physician performs a physical examination which often involves searching for characteristic signs of the disease such as heliotrope and gottron papules. Laboratory exams may include getting the muscle enzyme levels, magnetic resonance imaging, muscle and skin biopsy, chest x-ray, ultrasonography and electromyography. ^[1]

Treatment

Medications that counteract the inflammation such as steroids are often prescribed. Some may be given immunosuppressant drugs like azathioprine. Calcinosis is common among pediatric patients. This can be removed through surgery.

References:

1.      http://emedicine.medscape.com/article/332783-overview#a0101

2.      http://www.nlm.nih.gov/medlineplus/ency/article/000839.htm

3.      http://www.rheumatology.org/Practice/Clinical/Patients/Diseases_And_Conditions/Dermatomyositis_%28Juvenile%29/