Originally Posted by WarChild

Dogs have what is known as an "Itch threshold". What that means is several factors can contribute to to them being itchy. It could be just fleas, or just a food allergy, or just an enviromental allergy, or a combination. It might be that a mild case of fleas alone is tolerable to the dog, but combined with a mild allergic reaction it sets them off itching.

The first thing you want to do is make sure the dog has a good flea control system. I'd go ahead and use Sentinel, it's a pill given once a month. Not only does it kill adult fleas, but it also kills other parasites including many forms of common worms.

If the dog is already on a good flea control system and there is no evidence of fleas, remembering that you may not even notice a mild case without careful inspection of the skin for bite marks, then chances are good it has developed an allergy to the protein in its food. Switch the dog to a protein it hasn't normally consumed like Fish or Kangaroo. Iams makes a Fish and Potato and a Kangaroo and Potato blend that works well. Keep in mind that you will not want to give the dog Rawhide or any other beef or chicken products either.

If your dog has or develops hotspots, treat them by shaving the area and washing it good with a surgical scrub or another non perfumed soap like Hibatane. Your vet will sell you a small bottle of surgical scrub very cheaply. Keep the area as dry as possible until the hotspot heals.

Finally, be sure that if you are washing your dog that you are using a pure, non scented wash because it could be something in the shampoo causing a mild reaction too.