3 Answers

I know you use ammonia on wasp stings so I imagine it would be equally as good on flea bites.  My heart goes out to you, you must be miserable……..

First, get rid of the fleas. De-flea the dog, his bedding, the furniture and carpeting (if you have any), otherwise it's a waste of time to give him anything for the itch as the fleas will just keep biting. The best thing to use to rid the house of fleas is Diatomaceous Earth http://www.richsoil.com/diatomaceous-earth.jsp you can even sprinkle a light coating on the dog.

Brewers yeast for dogs (any pet store will have it) this is good for his skin and any irritation cause by the fleas.

Give him benadryl for the itch because he could have an allergy to the fleas. 

The dosage for dogs is 1-2 mg per pound of body weight administered every 8-12 hours as needed.  Source: http://www.vetguru.com/2011/10/04/benadryl-for-dogs/

Add some garlic to his diet. The garlic is good for him and fleas hate garlic.

Safe dosage amount of garlic for your dog 

10 to 15 pounds - half a clove

20 to 40 pounds - 1 clove

45 to 70 pounds - 2 cloves

75 to 90 pounds - 2 and a half cloves

100 pounds and over - 3 cloves 

Source:http://www.natural-dog-health-remedies.com/garlic-for-dogs.html  

If it is seasonal ( winter) Psorinum 200 in dillution 10 drops of medition with 20 ml water twice a day for two to three days. Hope it will be cured. It is a homeopathic medicine therefore pour the medicine in the mouth so that it comes in contact of the tongue mostly.