UPDATE - Recurring Poison Oak

Thanks for the response, albeit conflicting. I have since found lengthy discussion threads of sympathetic eczematous afflictions occurring in the exact location of former Urushiol-induced contact dermatitis (Poison Oak). It occurred to me that many plant-based inks have been used for long lasting tattoos. Why couldn't the Urushoil linger in the skin as long as the pigments?

Here's the update: The rash has preceded a Herpes outbreak by a day or so. Coincidence? Could it be that the immune system, while busy attacking the Herpes, has neglected to protect the area on my arm? Maybe the Herpes outbreak triggered a general hypersensitivity in the skin(?).

Can the skin be damaged to a point that it is subsequently vulnerable to other attacks (pollen, fungus) and more likely to have a histamine reaction in the compromised zone? Judging by the number of similar help requests floating around the internet, and the lack of response, the "recurring Poison Oak" issue is worthy of academic study. Maybe it's less work to prescribe Prednisone.