I have 2 Boxers that are 5 years old. One of them has been having troubles. They are both on Frontline and Heartguard. The one that has been sick came down with a high fever 104 for 4 days. He was urinating on himself and extremely lame. He then had alot of swelling on the right side of his face affecting his eye and nose and lip. He was put on Cipro and Amoxicillian for 15 days.............he was feeling fine after the meds for about 2 weeks and then it all came back. He got very lame again, high fever, and swelling again only this time the swelling was on his inner thigh. He went on the Cipro and Amox again, but for 30 days this time. He has been off the meds now for 7 days and is becoming lame again and urinatine on himself. He has been tested for Lyme disease with negative results. I will call my vet again tomorrow, but have you heard of anything like this??