|It sounds to me like you have something that is still contaminated with the poison oil.
Years ago I had PI that kept reoccuring on my foot. It took me quite a few outbreaks to realize that my shoe was the cause of it. Once I stopped wearing those shoes, it stopped coming back.
The oil can remain 'toxic' for up to 5 years. So anything such as clothing, tools, glasses, etc. that has any of the oil on it can re-infect you.
Fels-Naptha soap is suppossed to be good for cleaning the oil off. There is another product called Technu, it is suppossed to be good for cleaning laundry, skin, and other items to decontaminate. In my case I just threw away my shoes.