Rheumatoid condition based on defence reactions to the body’s own cells and protein (an autoimmune disease). In this condition the skin and muscular tissue are particularly affected; in its acute form it is particularly common in children. The symptoms are accumulation of fluid (oedema), and pain in the muscles associated with loss of energy and swelling of the eyelids, and possible eruptions on the face and neck. General symptoms are fever, loss of weight and fatigue. All the muscles in the body can be affected, but usually the flexors of the limbs and neck are involved. If the respiratory muscles become affected there can be shortage of breath, and contracture can occur in the tissue concerned. Chronic dermatomyositis occurs in adults, beginning gradually, then increasing in severity. If the condition affects only the muscles and not the skin it is known as polymyositis. Malignant tumours, particularly of the stomach and intestine, occur in 20 per cent of sufferers. Laboratory tests show large quantities of muscular enzyme in the blood, a sign of muscular breakdown. Examination of pieces of skin and muscle show symptoms of inflammation and decay. Treatment is usually by large doses of corticosteroids and painkillers. Physio- therapy is important to avoid contractures.