Here is a question for you, maybe your GSP has had the same problem: "I.. and as of lately he has been having problems with his anal gland.
It's awful, and rare but it's a sure sign that someone needs to have their anal glands squeezed. Until a few months ago I naively had no idea.
Grooming your German shorthaired pointer! this does not mean the dog has worms, it means his anal glands are bothering him and he needs to have them.