What can I use on my dog to stop the itching?

Try bathing him with a oatmeal shampoo. I use Buddy wash on my pit (he has super dry skin) and its so creamy and conditions his skin. Try using organic products for your pit. Also food influences your dogs skin, try to feed him holistic dog food. None of that pedigree eukanuba crap. Both my pits get fed "taste of the wild" with a bit of evangers. And there skin has improved DRASTICALLY. My boxer also, I cant feed him kibble so I feed him Natures Variety RAW and he also had a skin condition. this food cleared it right up because it is natural. GOOD LUCK.

My dog is part pit and she had the same problem. We switched her food to Taste of the Wild. Grain free. Other brands are also grain free, like Blue Buffalo. It's pricey, but the shedding, scratching and chewing at her skin stopped.

Ask the vet if it is okay to use benadryl with the medication he is on. My dog had skin issues when she was a puppy and the vet put her on medication and also had me use benadryl to calm the itching. Benadryl is safe for dogs just I would check with the vet to make sure it is okay to mix it with the medication he is currently on. Just like in humans the benadryl can cause sleepiness in dogs so it can make him sleep a little bit more than usual. Also if the vet says it is okay to use ask them how much they would recommend to give him. (it usually goes by weight)