An additional thought: Based on my various skin issues over the years, it likely is as much a matter of breathability as a matter of allergies to specific substances. For example, back when I used to wear a watch, I had severe reactions to any metal, plastic, or rubber watch band. When I switched to leather, I still had some problems, but fewer, especially if I wore the watch very loosely, such that neither the watch nor the band was in contact with any part of the skin continuously. I did best when I switched to fabric watch bands, which I still had to wear very loosely--or else I got a reaction to the back of the watch and to the metal fastener.

Band-aids do not usually cause a problem, probably because they aren't usually on for extended periods. But I do better with fabric band-aids than other ones.

So, in addition to the question of allergies to specific ostomy supply related compounds, it may be just as important whether there are products that allow oxygen to circulate to the skin underneath.