Seems this issue is haunting alot of people lately...try the following, and I know it sounds ridiculous:
Change your Non-Prim hair.
I had a similar issue ages ago...that fixed it. Someone posting in the "Abandon 2.0 thread" had this issue, and I got inworld to help her out...changing their non-prim hair(usually a "Bald Base") worked. A friend of mine 2 days later had the same issue. Hair change fixed it. No clue what causes it, or why it fixes it, but if it works I ain't gonna complain. =P
Only other option would be Eyes and Skin, as those are the 3 things you "always" have to wear some form of, and when changing nothing else works, that kinda narrows it down Hopefully, anyways...assuming something bigger isn't what's breaking you =(