THE MYOSITIS ASSOCIATION

The Myositis Association (TMA) is a non-profit,

voluntary health agency dedicated to improving

the lives of people affected by myositis. Formed

in 1993, TMA has grown from 16 patients, who

helped form the organization, to more than 6,000

members who have been served by TMA.

TMA is governed by a volunteer Board of

Directors that includes patients, family members

and interested professionals, bringing diverse

strengths and perspectives to the organization.

Through member newsletters, publications,

support groups, research and advocacy, TMA

helps those who have myositis today and works

to prevent any others from having to experience

myositis in the future.

Der

mat

omyo

sitis

“Myositis” describes inflammation or swelling ofthe muscle tissue. General muscle inflammationcan occur after exercising or taking certain med-ication, or it can be from a chronic inflammatorymuscle disorder like dermatomyositis (DM).Although the underlying causes of the DMinflammation are not known, some doctorsbelieve there is an environmental exposure (per-haps to an infection or sunlight) that triggers thedisease in someone who has certain specific butnot yet fully defined genes or gene sequencesthat predispose him or her. DM is a rare disease,and all forms of myositis (polymyositis, dermato-myositis, and inclusion-body myositis) combinedaffect about 50,000 people in the U.S.

DM affects people of any age or gender but itis more common in women than men. It is themost recognizable form of myositis – and there-fore easiest to diagnose – because of the visibleskin rash. Some of the first signs of DM are:

• A patchy, dusky, reddish-purple rash on theeyelids, elbows, knees, or knuckles. Rashesmay also occur on the cheeks, nose, back, andupper chest;

• General tiredness;• Trouble climbing stairs, standing from a seated

position, or reaching up;• Scaly, dry and/or rough skin.

Several sub-types of DM are: overlap myositis,when the patient has at least one other autoim-mune disease (such as lupus, scleroderma, orarthritis) along with myositis; amyopathic der-matomyositis, or DM sine myositis, when theskin is affected but muscles are not involved; andcancer-associated myositis, when the diagnosesof myositis and cancer occur within two to threeyears of one another.

Inflammatory myopathies are classified asautoimmune diseases, meaning the body'simmune system, which normally fights infectionsand viruses, does not stop fighting once theinfection or virus is gone. The immune system ismisdirected and attacks the body's own normal,healthy tissue through inflammation.

WHAT ARE THE SYMPTOMS OF DM?

Patients often experience the skin rash of DMbefore the muscle weakness. The rash may bepainful or itchy, or it may cause no discomfort.The rash and weakness are caused by inflamma-tion of the blood vessels under the skin and in themuscles.

Patients usually experience muscle weaknessgradually, developing over a period of weeks ormonths, and some patients experience muscle pain.The muscles most often affected are those closestto and within the trunk of the body – neck, hip,back, and shoulder muscles, for example. Somepeople have trouble swallowing (dysphagia),hoarse voice (dysphonia), painful joints, and othercomplications.

HOW DO DOCTORS TEST FOR DM?

Your doctor may first ask you questions aboutyour health in general, including your health histo-ry and when you first saw signs of skin rash ormuscle weakness. He or she will then do a physi-cal exam to assess muscle strength and skin symp-toms, and will typically ask the hospital's lab torun one or more of the following tests:

• Blood tests for muscle enzymes (including CPKand aldolase tests) and other blood factors

• Muscle biopsy

• Electromyogram (EMG) and nerve conductionvelocities (NCV)

• Magnetic resonance imaging (MRI) of the legmuscles

Your doctor may order other tests to rule outother diseases or conditions. If you have questionsabout any test, be sure to talk with your doctor orlab technicians, or visit TMA’s web site atwww.myositis.org.

HOW IS DM TREATED?

Medicines used to treat DM aim to slow theimmune system and stop the inflammatory attackon the muscle, skin and other body systems.Prednisone, a corticosteroid medicine, is ofteneffective as a first-line treatment in controllingthe inflammation and increasing muscle strength.Your doctor will monitor you for possible nega-tive side effects, including weight gain from fluidretention, osteoporosis, cataracts, mood swings,high blood pressure, and diabetes. (Diabetes isan increased risk if the patient has a family histo-ry of adult-onset type-2 diabetes, or is over-weight.) You and your physician should carefullyconsider the potential benefits and risks of thisand other medicines.

Your doctor may prescribe other immunosup-pressant medicines – medicines that also slow thebody’s immune system and inflammatoryresponse – to be used in place of or in addition tocorticosteroids. When used in combination witha corticosteroid, the additional immunosuppres-sant allows patients to use a lower dose of thecorticosteroid, thereby lessening the corticos-teroid’s undesirable side effects. Immunosup-pressants include methotrexate, azathioprine,and cyclosporine. Intravenous immunoglobulin(IVIg) has been used with some success in treat-ing difficult cases of DM. Some medicinesrequire extra caution, and your doctor will moni-tor your blood tests closely. Other immunosup-pressants are being studied, and there is consid-erable work currently underway to develop newand more effective treatments.

Sometimes physicians prescribe topical formsof corticosteroids or other medicines to treat theskin symptoms. Your doctor will talk to youabout complementary, non-medical treatmentlike physical and occupational therapy, appropri-ate exercise, and especially sun protection, sincein many cases exposure to sunlight exacerbatesthe disease.

WHAT IS DERMATOMYOSITIS (DM)? www.myositis.org