Can Tic and Flea collar cause dog health problems?

[Jerry_NJ]

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.

[Jerry_NJ]

Not a Harts collar problem. Dog was diagnosed with lymn disease in mid May.
Antibiotic seems to have cleared problem. He's back to normal old dog limitations

[specialmom]

Sorry I didn't see your post.  That is sad to hear about lyme's disease!  I had a dog get a tic over her eye and was worried about that.  Anyway, glad that you got your answer and it is all cleared up.  Have you ever used the flee and tic drops you get at the vet's?  The kind you put on just once a month and rub it into their shoulder blades? I'm looking into that. More expensive but said to work well. How long was your dog treated before you were confident he is better?

[Jerry_NJ]

Dog on antibiotic prescription for 15 days.  He appears to have recovered.

The topical solutions such as Frontline anti tic seem to be effective but nothing is 100%.

[Jerry_NJ]

Just checked back.  My dog showed improvement in first day on antibiotic.  In two weeks he appeared to be fully recovered and remains so today, months later.  I have used Front Line on several dogs but do not use currently.