An allergic reaction to the oils in poison ivy is quite common. For most people, there is no need to visit the doctor. Keep the rash clean and dry. For itching, find a topical solution that works for you. There are a number of them on our cures & treatments page. The rash normally runs about 10-14 days though there are a number of cases that will run up to 3 weeks. For me, I find that my reaction is about 14 days. If you find that there is severe swelling or the rash is in sensitive areas like around the eyes, you should consider seeing a doctor. Hope this helps!