Poison ivy and poison oak contain urushiol – a colorless and odorless substance – that causes rashes when someone comes in contact with it. This substance is released when Poison ivy rash is quite common among kids but adults too can get the rash. Poison ivy rash may even produce blisters, swelling and cause itch. Poison ivy rashes can be healed with home remedies. The simplest way to heal poison ivy and oak rash is to wash the affected area with soap first and then with salt water. Here is a list of the other and most useful home remedies for poison ivy rashes and itching.