u/FurrySuperset52

So a cotton shirt that I have worn for 2 years now without any issues has just recently started causing me to burst out in hives. I was wondering what could be the cause. I've never had a problem with it in the past, but it's been 2 months since it started giving me hives only on my upper body where it's touching. It's 100% cotton just like my other shirts except they don't cause flare ups. Just this particular shirt. And yes it's fully cleaned plus I've tried in many situations and the shirt is the only variable causing issues.