I have a rescue mix Chihuahua Pomeranian weighs about 12 pounds most of his 6 years with me. He's estimated to be 12 years old and has been taking glucosamine supplement for several months due to problems with walking. More recently he has lost weight and become very lethargic and has even lost appetite in the last few weeks. I put a Harts Ultra Guard Flea and tic collar on him April 11, and his condition has worsen, starting after the new collar was put on him. I took the collar off yesterday, and he is eating a little again. My question is based on my suspicion that he may be suffering from an allergy to something in the collar. Seek any advice, short of seeing vet at this point, on the likelihood/experience with problem with dog health due to chemicals in tic and flea collar.