WHAT IS DERMATOMYOSITIS?
Dermatomyositis is an inflammation of the muscle tissue that is characterized by a skin rash and muscle weakness. This disease affects both children and adults, but it affects nearly twice as many women as men.

WHAT ARE THE SYMPTOMS?
Dermatomyositis is characterized by immune inflammation of muscles as well as by the presence of a rash. This rash, which appears as a purple or red discoloration of the upper eyelids, is present in almost all children with inflammatory myositis. Scaly red lesions over the back of the fingers at the knuckles or over the elbows or knees may also occur. Muscle weakness is most common in the muscles closest to the trunk of the body, like the neck, back and shoulders. This weakness may lead to difficulty rising from a sitting position, climbing stairs, or lifting objects. Problems swallowing, called dysphagia, may also occur.  

Occasionally patients can develop the rash with no evidence of muscle disease, a condition which is known as "amyopathic dermatomyositis." People with dermatomyositis may also have lung inflammation (pneumonitis), and children may have an inflammation of the blood vessels (vasculitis) and calcium deposits in the skin referred to as calcinosis.

HOW IS IT DIAGNOSED?
A diagnosis of dermatomyositis is suspected when patients complain of difficulty performing tasks that require muscle strength or when they develop certain rashes or respiratory problems. To establish a diagnosis, a muscle strength examination will be performed to determine if true muscle weakness is present. This likely will be followed by a blood test to measure the level of various muscle enzymes like CPK, an electromyogram to gauge electrical activity in muscle, and finally a biopsy of a weak muscle. Sometimes MRI scanning can help to establish the presence of abnormal muscle. Blood may also be tested for the presence of myositis-specific antibodies (immune proteins), which help to establish a diagnosis and give some information about prognosis.

HOW IS IT TREATED?
Dermatomyositis is usually treated with medications. An oral corticosteroid such as prednisone (Deltasone and others) is usually administered in high doses once the diagnosis has been established. Blood muscle enzymes usually return to normal in about 4 to 6 weeks and patients gradually regain strength in 2 to 3 months. Methotrexate or azathioprine are usually added to ensure better long term control of the disease and to avoid long term side effects of cortisone such as weight gain and redistribution of body fat, thinning of the skin, osteoporosis, cataracts and even muscle weakness. In severe or treatment-resistant cases additional measures may include intravenous immunoglobulin (IVIG) and other immunosuppressive medications including cyclosporine (Neoral, Sandimmune), tacrolimus (Prograf) or mycophenolate (Cellcept).

Patients with a rash should protect themselves from the sun by limiting time outdoors and using sunscreen when they do go outside.

WHAT IS THE PROGNOSIS?
Most cases of dermatomyositis respond to therapy. The disease is usually more severe and resistant to therapy in individuals with cardiac or pulmonary problems, so these individuals may need to experiment with several different therapies to find the one that works best.

SUPPORT GROUPS
Crescent Healthcare is proud to support the efforts of patient groups like the Myositis Association. On their website you will find more information about dermatomyositis and the local support chapters.