I don't know is the honest answer and we don't often see people talking about the bags here. But I see that they may be attached to your skin by adhesive sometimes. My stoma bag is stuck on and when I was given some that I was allergic to I did have an itchy rash because of that. The GP and stoma nurse helped me control the itching by changing back to my usual bags which have adhesive that I'm not allergic to and prescribing a lotion to treat the rash. It took some time to calm the reaction, but I do have a number of allergies. Heat can make the itchiness worse of course.
If that sounds as if it might be what you need I hope this helps you ask for help.
