itchy red bump disease.

what is the medical name for this disease>I have had a strange rash that begin with one red bump on the inside of my left bicep the end of June '06.  A couple of weeks later it went down only to return a few days later.  Each time it went away, it returned worse then a bump showed up on my right arm - similar location to where it initially started on my left arm.  About six weeks ago the itching became too much.  By this point it has spread pretty well through the front of my torso itching a lot.  Somties it would go down slightly but would never go away.  SHowers - jsut eh warm water - would aggravate it and make it look much worse.