I have a weird allergy myself. I'm allergic to a chemical called thimerosal. It's a mercury derived preservative that's used in a lot of soaps, bodywashes, etc., and is also used as a preservative in a lot of vaccines, though here in the U.S. the CDC has phased it out of the new vaccines. My skin breaks out in little bumps that get a clear liquid in them and itch me like hell that then dry up and dry out and crack my skin.

Don't even want to know what it would do inside of my body. >.> Problem is, it does by about ten different names as a preservative and when I'm out and about I don't know what it might be in, so I have to carry around my own soap. I don't wear anything about it to alert people as it's not severe enough on my skin to kill me, just is annoying, but when I was in the hospital before I had a bracelet on for it. One time I used bodywash that broke me out all over my body too, and that totally sucked. -_-