Itching all over is an annoying sensation often caused by skin irritation or inflammation. Itching all over may be associated with a rash or other skin symptoms, or it may occur by itself. Itching all over can be caused by a relatively mild condition, such as dry skin and a build-up of dead skin cells. For example, if you feel itchy all over and you live in a dry climate, you may have “winter itch” caused by the lack of moisture in your skin.