Quote Originally Posted by lily27 View Post
Personally, I have an allergy to nickel. Unfortunately it is a very common filler-metal, and is in just about everything. I have to be very careful about the jewelry I wear.

I also reacted to the metal bits on my first training collar. I was really upset and wore it anyway (despite the itchy red rash) until Master ordered me to put it away (and replaced it with one that didn't bother me).

My guess is it is a reaction to the metal... and apparently nickel is an increasingly common sensitivity. Going with stainless steel sounds good to me as well.
Unfortunately Stainless steel is made of three main alloys, steel, nickel and chromium. The larger the nickel content the better the stainless steel. Might be best to test her for allergies to nickle before investing in stainless chains.