What Causes Itching All Over The Body?

I have itching problems like a rash, allergy reaction but no rash or redness of the skin has appeared, but the itching symptom is traveling, first i feel it on the top of my foot, then on my forearm, then the back of my head, etc…. Only from 30 seconds to a couple of minutes in each area, then it moves to another area. Ant thoughts?