Myson, I thought I had nickel allergies in the past (can't wear cheap earrings without getting red earlobes and a lot of itchiness there) and when I mentioned that the allergt might cause a problem for my replacement, my OS procured from Biomet, which made the Oxford implant he was planning to use on me, 2 disks, one cobalt, one titanium and I had to keep each disk taped to my arms with paper tape for 1 week. I had a terrible reaction. My arms were very red and itchy where the disks had been. So my OS, when he saw that reaction, sent me to see a dermatologist for further testing. The dermatologist told me that the 7 day test was too long and said I should do a 3 day skin patch test on my back (which included a nickel test) as well as having me tape the disks again to my arms so he could see what happened. DUring the 3 days of testing, my husband stuck some paper tape on my back to keep the testing panels on there. When I got back to the dermatologist after 3 days, he removed the stuff from my back which revealed no reaction to the nickel test and a slight reaction to fragrance. He also removed the 2 disks from my arms. From all this testing, he determined I wasn't allergic to the nickel or titanium but had had a reaction instead to the adhesive on the paper tape. That was all last summer. My OS, along with the dermatologist, decided I would be fine with the Oxford implant and got it almost 6 months ago. Thankfully I haven't had a problem at all. I'm sorry you've had such issues. I can't imagine how awful it must be.
At the time of my allergy testing which was in the beginning of July 2008, I started a thread in the Unicompartmental area of the Knee Arthritis part of the web site asking if anyone else had had such testing. No one answered so I answered myself and said I must be the only one who ever had this testing. I don't think it's very common. I think I may have even posted a picture of the reaction I had before I found out it was the tape that I reacted to. FYI, I live in the US (Connecticut).
I hope this has helped you somewhat.