Diagnose Skin Disease - Page 2

I was feeding him RC so as to rule out any allergy i stopped feeding him RC. 

I didn't understand what Avil is ??  You said you gave some to your dog??  Updated .. looked it up .. Avil is an antihistimine.  First time using Advocate or Kiltix??  Any vaccinations recently??  Anything new before the symptoms appeared??  Has your dog been kenneled for a weekend or to a new place where fleas from other animals were present??

Avil is antihistamine. Chlorpheneramine maleate. Yes he was vaccinated in feb 2015. No this is not the first time I am using advocate. Used many times before. Killtix yes this is the second time.  No recent kenneling. Always with family. He goes out for walks and of course there are many strays. But they keep distance seeing him. Yes he had itching so only i applied advocate. 

My best guess is flea dermatitis .. the fleas were already on the dog and they bit before dying.  If my theory is correct the symptoms should abate if not then I have lots of clues but no solution.

Do chemicals present in frontline, advocate and killtix interact? 

It looks like fleas to me as well.

Interesting side note... I had my 10 yr old female vaccinated for rabies last year before her spay. She had not had routine vaccines in quite some time (we are minimalists) and quite literally the next day, her rear end was one giant weeping hotspot. She was on spinosad at the time (comfortis) so no fleas. It just would not clear up, and she had NEVER had a hot spot before. Out of desperation, I gave her a double dose of bennadryl and the itching stopped. 3 days of the double doses and it cleared up. I believe, without a doubt, that her reaction was caused by the vaccine and started almost identical to what your girl has.