For topical treatment, we use nustock. http://nustock.com/ It smells very old fashioned (like camphor) and is all natural - and takes care of the itchies pronto.

But you do need to address the cause of the itch. And it's usually fleas or mites. And the best way to take care of them is baths.

Frontline works but if it freaks you out, you can rub citronella oil through your dog's coat every couple of days. But that can cause a reaction too.