The beginning of polymyositis can be acute or subacute. Acute viral infection sometimes precedes or is the starting factor of manifestation of the disease, the most frequent signs of which are a weakness of center proximal muscles or skin rashes. Painful sensations are less expressed than weakness. Perhaps the development of polyarthralgia, the phenomenon of Raynaud, dysphagia, infringement of the lungs, common symptoms (fever, a decrease in body weight, weakness).