My mother has been on Tarceva since October - 100mg every other day.The first three weeks she was on 100 mg a day and it gave her severe abdominal cramps, diarrea and THE RASH.
Once she was prescribed 100 every other day some of the symptoms subsided, the rash did not. She is a nurse and knew that a steroid could help the rash and asked for prednisone. The doc ok'ed it reluctantly. She only takes the steroid when the rash becomes painful. We credit the steroid with helping her appetite and self esteem.
Tarceva was one of three drugs mother started and something is doing something b/c she has had shrinkage of the tumor during MRI in December and February.
Good luck.