Remicade and hair loss

I have been on remicade for 18 months and it has been terrific in helping my CD.  However, in the last 2 weeks I have noticed severe head loss all of a sudden.  Have others experienced similar occurences after this much time?  Does the hair growth/losses go in phases?  I have gone from a thick head of hair to very thin and patchy hair in two weeks.  During this 2 week periord, I have felt completely healthy.  Very shocked and concerned about this.  Thanks.