Can You Give A Dog Benadryl For Itching?

Yes you can give Benadryl to dogs.  The dose is 1 milligram per kilogram of body weight given orally every 8-12 hours.  Do NOT use the Cold and Sinus variety--only plain Benadryl is safe.  It comes in 25 milligram capsules and a Children's Liquid.  Benadryl can cause drowsiness.
If this does not help or these bumps do not resolve in 2 days your dog needs to be examined by a veterinarian to find the underlying cause of the bumps and look for any secondary infections (bacterial, yeast, mites).

Yes, it depends on how big the dog is though. You should call the vet about this, but make sure you can tell them how much the pup weighs.

Yes, you can my boxer charlie broke out in hives all over his body and he was non stop itching and i took him to the vet she said that benadryl is the best and only thing you can give your dog, you need to know how much your dog weighs, my boxer weighs 53lbs so the vet told me to give him 50 mg of benadryl so if your dog is half then 25 mg, he probably got stung or got bit by a bug, hope that helps

Yes you can give it.

My dog weighs 78 pounds how much benadryl can he have

Yes, I would only give 1 capsule a day if needed. Don't give this to a puppy.

My dog has the same, except shes pregnant, does this make a difference?

No, your dogs has fleas  give him a bath.