How does poison ivy begin to grow?

Acutally, you can't spread and poisonish rash (ivy, oak, suma) by itching it. You will only infect the area. Other rashes and blisters appear, because you have thicker skin in the areas where the rash pops up later, than where it pops up sooner. (i.e. your face nack and forearms and legs will have the rash first, then a few days later your hands and feet will show up, it all depends on the contact with the oil from the plant and how long it takes your body to react to it. It is NOT contagous and CAN NOT be spread by itching or touching the rash and/or blisters.