Can someone help me out here ? My 2 year old is doing alot of scratching and biting at his stomach and rear end. I just had him at the vet the other day and had his anals cleaned. Could that be botherig him ? I also gave him a bath and usd the same shampoo I always used. Should I try an anti itch shampoo or just back to the vet ? I was also told to try and give him benadryl. Is that safe for a dog ?