What Causes Bruising And Itching All Over The Body?

For the last 6 weeks I have had itching that started in my crotch area and now has spread under my arms, arms, stomach. Now I itch all over the rashes have turned to looking like bruising. I also have a bit of a sour stomach. It seem like when I am laying in bed are sitting for a long period of time the itching just comes on real fast and I itch all over.