It is the name given to a condition that results in severe stiffness and pain in the muscles of the neck, shoulders, lower back, buttocks and thighs. The muscles of the forearms, hands, calves of the legs and the feet are usually not affected. In addition people affected by polymyalgia rheumatica may experience weariness and loss of energy, night sweats and fevers, weight loss and depression. These symptoms are often worse in the morning hampering early morning functions such as rising from bed, dressing and washing. Often tasks cannot be undertaken until the afternoon.

Often the onset is dramatic. A previously fit person can retire to bed in good health and awake to find themselves "cast" with severe stiffness and pain. In other cases the onset can be more gradual. It may start with some stiffness in one group of muscles (eg the shoulders) and spread over the next few weeks to involve the back, buttocks and thighs. If it is not treated, the severity and site of the symptoms may vary over several months.

The cause of polymyalgia rheumatica is not known. It does only occur in older people and it may be triggered by virus which alters the way in which the body's immune system works. It responds well to treatment although for some people it may develop into a form of rheumatoid arthritis.