I find that the UHFs get less soft with washing. When they are new, the inside feels almost like Cashmere. After several washes, that soft hair feeling is no longer then. However, that may help you if it's the hair-like quality that you're sensitive to.
Sensitivity to fabric is dependent on (1) average fiber thickness (2) maximum fiber thickness and (3) your sensitivity. I would assume in this case it's (3) which is the driving force. I'm extremely sensitive to wool shirts but have no trouble with the UHFs.
I posted a few pages back my results from washing my M at 30 deg. You can expect some shrinkage in the length and sleeves but pretty much none in the chest.