Steroids/how long they take to leave...

Ripley had to go on a very mild steroid for his skin issue to clear up. I can't remember what it's called (it's written on the bottle at home), but he just finished them recently. I've never had a dog on any type of steroid before so was just curious if anyone knows how long they take to leave their system? It affected his temperament poorly and I look forward to having my good, sweet Ripley back. It was the only thing that was going to clear his skin thing up, so that's why we had to put him on it (and I believe it worked - he looks better than he has in forever and is not itchy or stinky anymore). But he's been such a grouch the whole time he's been on them. No tolerance for other dogs, less tolerance for things that he is normally comfortable with and likes, etc. He is the last dog in the world who would normally snark at anybody or anything, especially people, and lately he's just been a jerk. Not to the point of being dangerous and he knocks it off when I tell him, and most of the time he seems normal, but he seems to be going through mood swings or something. Happy go lucky and normal one moment and shortly after he's growling and getting irritated by things that should not irritate him. And he's been a lot more irritable, worried and stubborn too and just acting weird. Like this morning I told him to get in the house and he tucked his tail and just stood there, then went onto the yard looking slinky and then finally into the house. His patterns and behaviour have all just been off. Mind you, we did have company for a week and that could be part of him being out of sorts, but that's never affected him much in the past. I hope it's just the medication as all of these things started shortly after we started giving it to him, so it would make sense. I just hope it leaves his system soon and he gets back to normal.