Arnie is a 12 year old neutered male. He's had arthritis in his hips for a long time now, and his posture is greatly affected. A couple of weeks ago his back left knee joint was so swollen that we took him to the emergency vet, fearing it was broken. They performed x-rays and determined it was really bad arthritis. He's also been having terrible problems with his skin. A few months ago he developed severe acne on his chin. We treated it with what the vet prescribed: very mild benzoyl peroxide and topical ointment. It was suggested to us that it was a result of stress. This week, Arnie's arthritis is better, but his skin is worse than I've ever seen. It's not acne anymore, but what appears to be severe psoriasis - he has open sores, scabs, and bald patches all over his head and neck. He has had instances of conjunctivitis in his eyes. He has also lost 2 pounds over the course of the last year, but he isn't eating any less. We took him to his regular vet who did a lot of bloodwork (to check his thyroid, etc.) and all of the tests came back negative. Could this be Psioratic Arthritis? If so, what would be the best thing to do? Allergy tests?