Has anyone ever heard of allergic reactions to any kind of gear whether PH or actual AS?

a buddy of mine is allergic to the enthanate ester.
Lift heavy and eat lots of dead animals! Yes, that's me in my avatar.
Some people have an allergic reaction to 1-Test products. Some have gotten bad hives and have come close to anaphalaxis.
I've read of a few bad reactions to 6-OXO as well.
Bottom line is you can be allergic to anything.
I have, but very, very rarely.