canine condition concerns

Question
Hello,

I own an 8 year old male chihuahua, neutered.  He suffers from chronic tooth plaque, and my vet just mentioned that he wants me to consider him pulling the bad teeth.  Aside from that he has been a healthy pet.  

However, this fall, in Massachusetts, is the first time he has been infected with fleas.  We have used a few flea spay killers on some spots of the house, vacuum like there is no tomorrow and bathe him with medicated soap.  I gave him one Capstar (6 weeks ago) it did not help.  I gave him some bio spot on his back and he licked some, but is ok.  

The last week he limps and favors his left front paw (checked for swelling, objects, cuts, etc, and there is nothing visibly wrong).  He eats more slowly now, eats the same amount, drinks a ton of water, and goes outside to do his thing (in our enclosed yard) regularly.  No diarrhea.  Comes over to be pet and caressed when I watch the news.  Is aware and barks at intruders or weird neirborhood noises.

I just gave him a bath.  He has some sore, except that they are not really sore.  Just like skin peeling off, on his underside.  While his skin is light and pink, the "condition" is a rusty color, no texture or peeling off.  More like spots, or some rash.....  The gray sweatshirt where he was lying was thrown out as it had a large dark stain where he was lying with lots of little dark spor ( I pressume are flea droppings).

I have given him (three days ago) an 1/16 of a 200 mg advil wrapped in a bit of ham, his favorite.  An hour later or so, he walked about as if nothing was wrong with him.

He stunk as if of rotten meat when I bathed him earlier.

Sorry for such long inquiry.

What can be wrong, what can I do?

Thanks a lot!!

ervinsantiago@aol.com

Answer
An advil is very toxic to a small dog, so please avoid that.  The insecticide in Biospot, permethrin, only works for a few days, so I would recommend Frontline TopSpot or Advantage.  If the dog's skin is changing color or flaky, you need to see the vet.