How are muscles damaged in myositis?
Myositis literally means muscle inflammation. Dermatomyositis means inflammation of the skin and muscles. Together, they are called inflammatory myopathies. When skin or muscle tissue is inflamed, it has been infiltrated by white blood cells called lymphocytes. Lymphocytes are the police force of the body’s immune system. They are supposed to protect our body from foreign invaders, such as bacteria and viruses. They constantly patrol the body, on the lookout for things that “don’t look right.” When an area of the body is infected, white blood cells are signaled. They can multiply and head for the infected tissue to attack and remove the invaders. However, in inflammatory myopathies, lymphocytes also infiltrate healthy muscle fibers. This infiltration causes inflammation. It damages healthy tissue. Eventually, it can destroy muscle fibers. After the fibers are destroyed, scar tissue replaces healthy tissue, and there is no longer function in that muscle tissue. When skin is attacked, ra
