The seed and nut and most of the veggie allergies (what most of the other oils are) fall under my nickel allergy umbrella. As a teen it was only to where I couldn't wear certain jewelry, and now it's to the point where I have to eat a low nickel diet. I don't have any metal fillings from the dentist, either.
Other oils, like avocado, are the latex allergy, which actually does effect my ability to breathe (whereas nickel just gives me a terrible rash).
In my case, I think the underlying issue is autoimmune, because there are other things going on in that vein. But good luck getting that narrowed down when most doctors blow you off with your laundry list of symptoms (and this is common for most autoimmune folks, apparently the average to get a diagnosis is about a decade, which I have crossed). If I could afford going to see a holistic doctor, I would!