GDen,
It's very interesting that I found your post... I too have a couple of symmetrical dry patches of skin on the outside of each arm in exactly the same location on each arm. I have had this type of patchy skin before (and I've had dry skin all my life), but this is the first time I've noticed it being in the same location on each arm. I am taking Asacol, like you... so maybe there's some correlation there. ...interesting