Your dog has been itching for months now and i have tried medicated shampoo and taking him to the vet what is causing these horrible bumps?

Maybe you need to take your dog to another Veterinarian for another opinion. What did your first Vet say was the reason? Dogs can have Allergies to many things. A Vet can test him or her for what type of allergies your dog may have but it is expensive.

Fleas are the most common thing to cause skin allergies. A poor brand of dog food or a poor diet can also cause food allergies. Make sure your dog is on a good name dog food that does not have wheat or corn in it. Check the ingredients in your dog food. I recommend Innova or Natural Choice. Don't get any food that says "by products" on it such as chicken "by products. You want to see the Word "meal" such as chicken meal or lamb meal or Turkey. You don't want to see wheat, corn, soy, etc in the ingredients.

As far as fleas go, it only takes one flea to jump on your dog and bite him or her to set off an allergic reaction in the skin if the dog is allergic to fleas. Use the once a month flea & tick preventative, Front Line or Advantix. You just put them on topically, right on the skin but you have to do this once a month. It will repel and kill all fleas and ticks. Your Vet may want to add some cortisone to this to reduce the inflammation set up in the skin with drugs such as Predisone but not for a long period. So get that flea prevention going and make sure you are feeding a good name brand dog food. Not the cheap kind found in the grocery stores.