wipe rash??

My lo is 4 months old and all of a sudden has been breaking on his private area and his butt. Been using cream and such but I switched to just water and wash rags for a few days it went away then went back to wipes. And now he's broke out in a rash again. Anyone else have this problem suddenly because of wipes? He didn't have sensitive skin before, can he just develop sensitivity all of a sudden. I'm going to switch wipe brands and see if that helps if not I may have to just keep using wash cloths for a long time!