Hi and welcome to our little MS community,
Uticaria is not directly caused by MS, it definitely can be a side effect of many of the different medications used to treat MS though, people with hyper skin sensitivity can even react with hives just from the coating on some tablets, but the disease modifying drugs from memory have more commonly been associated with hives.
Cheers.........JJ
I have not heard of hives with MS but I do not know? I have heard of itching with MS.
Alex