My German Shepherd was on Rimadyl and high dose steroids too (100mg a day) when he had Anal Furuncleosis. He was diagnosed with it in April 2004 and we had to have him put to sleep in July the same year. He would have been six years old in the August had he lived. I have since read that dogs shouldn't be on steroids if they are on Rimadyl which I knew nothing about, I just went with what the vet recommended.

So sorry to hear about your boy 'Ben'.