Other organs are frequently involved in myositis, particularly the skin and lungs.
Skin changes in dermatomyositis may vary and can resemble systemic lupus erythematosus (SLE), but the most typically seen symptoms for dermatomyositis are the heliotrope rash on the eyelids and Gottron’s papules on the extensor surface of joints (Figure 2). Another type of skin rash is erythema, which has a distinct localization and shape: the so called V-sign and the Shawl sign; however, diffuse erythema, hair loss, and pruritus may occur.
Lung and other organs
Other organs that show signs of inflammation during polymyositis and dermatomyositis are the lungs during interstitial lung disease (ILD), the striated muscles of the gastrointestinal tract when there are difficulties in swallowing, and the heart during times of myocarditis and cardiac failure or conduction abnormalities.
Another distinct subset of myositis has a clinical phenotype associated with the presence of antisynthetase autoantibodies; it is known as the anti-synthetase syndrome and is characterized by myositis, Raynaud’s phenomenon, ILD, arthritis, and skin changes known as “mechanic’s hands” (Figure 2) [18.Love et al., 1991].