I had a bad case of poison oak more than 10 years ago. My doctor diagnosed and gave me some medication, he said to take all of it even if the rash goes away because poison oak can cause a lot of problems as you get older. I don't recall what he gave me, my rash comes back at least once a year around spring. Sometimes it comes back more than one time a year in the same arm then it spreads I suspect I cause the spreading.