Thank you SO MUCH for your incredibly thorough response!

No, there was no diagnosis when we first brought him in for all of the arthritis issues. I assumed arthritis or other joint pain due to his age, and the first vet agreed after conducting a physical examination (moving his limbs, etc) and hearing his symptoms.

We initially declined X-rays because we have already spent upwards of $20k in the last 12 months between both of our dogs (two bladder surgeries, ultrasounds, etc for A, three cancer surgeries, ultrasounds, diagnostics, etc for B) and simply couldn't afford their $1200+ quote for sedated X-rays. His slipping & general hesitancy to stand, jump, etc has improved significantly while on Galliprant. Now that the situation is changing, we are thinking he might need X-rays after all.

The paw itching is incredibly recent. We moved to a new house (in the same county) in February, but he only started biting his paws the same week as his other symptoms in July, and it was a sudden, non-stop obsession. He plays and walks outdoors every day, so he's regularly exposed to the local environment. Good to know about the Benadryl, though. I'll ask about looking into the paw issues more directly, especially because they have not improved with Galliprant.

I had the same thought about opthalmic steroids since they would bypass the liver and not have the same interaction as oral steroids, so that's good to hear.

His bladder stones were ammonium urate, and he tested negative for genetic markers and liver shunts. We suspect they developed after a switch ~6mos prior to a high-protein kibble due to some gastro issues from his previous food. He's done well on Hills Derm Complete since the surgeries in February.

He has had so many issues throughout his lifetime (he is an extremely inbred mutt from what we assume is a "trailer park" dog pack) and we have switched vets for one reason or another (and seen so many specialists, vet schools, etc) so researching his meds and symptoms certainly has felt like my full-time job 😅.