Watch out! It could be scabies! My friend started itching real bad on his bum, and we all assumed it was poison ivy, but after a few months of itching, it had spread to his hands, arms, legs, genitals and so forth. We all thought he had poison ivy from taking a dump in the woods. I wont say anything else, except look it up on google, and compare your rash with pictures of other peoples rashes.