Poison ivy is not contagious and is not spread through person-to-person contact, according to the Mayo Clinic. The rash itself only occurs as a direct result of contact with the plant or direct contact with plant oils that have contaminated other items, such as clothing.
According to the Federal Drug Administration, the rash associated with poison ivy is the body's allergic reaction to coming into contact with plant oils. Although it sometimes seems as though it's spreading as more skin starts to react to the oil, the rash is not spread through itching or oozing blisters. It is also not possible to get poison ivy from coming into contact with another person's rash, says WebMD.