What Causes Itchy Dots On The Arms And Legs?

I have had extremely itchy dots showing up on my arms, legs, belly, chest, wrists and ankles. At first I thought alergic reaction but A: nothing has changed *soap, detergent, etc* and it's been spreading for the last week and a half. They are very itchy at times and bleed a lot. I do not believe it is chicken pox / shingles. What else could this be?