Dermatomyositis

A chronic inflammatory disease of skin and muscle which is associated with patches of slightly raised reddish or scaly rash. The rash can be on the bridge of the nose, around the eyes, or on sun-exposed areas of the neck and chest. Classically, however, it is over the knuckles. When the characteristic inflammation of the muscle (myositis) occurs without skin disease, the condition is referred to as polymyositis. Dermatomyositis is one of a group of acquired muscle diseases called inflammatory myopathies. The disease has a subacute (somewhat short and relatively severe) onset. It affects both children and adults. Females are more often affected than males. Dermatomyositis is characterized by a rash accompanying, or more often, preceding muscle weakness.The most common symptom is muscle weakness, usually affecting those muscles that are closest to the trunk of the body (proximal). Eventually, patients have difficulty rising from a sitting position, climbing stairs, lifting objects, or reaching overhead. In some cases, distal muscles (those not close to the trunk of the body) may be affected later in the course of the disease. Trouble with swallowing (dysphagia) may occur. Occasionally, the muscles ache and are tender to touch. Some patients develop hardened bumps of calcium deposits under the skin. Patients may also feel fatigue and discomfort and have weight loss or a low-grade fever. Treatment commonly involves a steroid drug called prednisone. For patients in whom prednisone is not effective, other immunosuppressants such as azathioprine and methotrexate may be prescribed. Recently, a drug called intravenous immunoglobulin was shown to be effective and safe in the treatment of the disease. Physical therapy is usually recommended to preserve muscle function and avoid muscle atrophy. Most cases of dermatomyositis respond to therapy. The disease is usually more severe and resistant to therapy in patients with cardiac or pulmonary problems. Both polymyositis and dermatomyositis can sometimes be associated with cancers, including lymphoma, breast, lung, ovarian, and colon cancer. The cancer risk is reported to be much greater with dermatomyositis than polymyositis. (See polymyositis).

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A progressive condition characterized by symmetric proximal muscular weakness with elevated serum levels of muscle enzymes and a skin rash, typically a purplish-red erythema on the face, and edema of the eyelids and periorbital tissue; affected muscle tissue shows degeneration of fibers with a chronic inflammatory reaction; occurs in children and adults, and in the latter may be associated with visceral cancer or other disorders of connective tissue. [dermato- + G. mys, muscle, + -itis, inflammation]

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der·ma·to·my·o·si·tis -.mī-ə-'sīt-əs n, pl -si·tis·es or -sit·i·des -'sit-ə-.dēz polymyositis that is accompanied by involvement of the skin and that is typically marked by reddish erythematous eruptions esp. on the face, neck, upper trunk and distal half of the limbs, by periorbital edema, by violet-colored erythema of the eyelids and region over the upper eyelids, and sometimes by cutaneous vasculitis or subcutaneous calcification

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n.

an inflammatory disorder of the skin and underlying tissues, including the muscles (in the absence of a rash it is known as polymyositis). The condition is one of the connective-tissue disease. A bluish-red skin eruption occurs on the face, scalp, neck, shoulders, and knuckles and is later accompanied by severe swelling. Dermatomyositis is often associated with internal cancer in adults, though not in children.

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der·ma·to·myo·si·tis (dur″mə-to-mi″ə-siґtis) [dermato- + myositis] a type of polymyositis with characteristic inflammatory skin changes, including the Gottron sign (discolored papules, especially on extensor surfaces such as the knees, elbows, and knuckles); poikiloderma; discolored eyelids and edema of the eyelids and periorbital tissue; and an erythematous rash on the forehead, neck, trunk, and arms.