Poor Eddie. He's really got a sensitive bum. As we suspected, his anal glands had started packing up again. The good news is he lost a bit of weight (0.4 pounds, which is more than it sounds when you start out at 18 pounds). And the other good news is we caught it sooner and now I know I did feel the glands.
He's to double his pumpkin intake and come back in three months. The vet wasn't all that sure that the fiber would help but it won't hurt and it does help increase the amount of water he's getting.