What can I do about my dogs itching and now dandruff?

My 12 year old Sheltie mix has had problems with itching ever since I adopted him 2.5 years ago. I take him to the vet at least 3 times a year when it gets really bad and all the vet ever does is, is give him a cortisone injection. Ever since Winter started, not only is his itching worse, but he has developed really bad dandruff. The way his coat is, you can only see a bit on the top, but underneath it's like a snow blizzard. I want to know if there's anything other then another shot of cortisone to help him with the itching, and now the dandruff.

Bathe the poor beast. They can recommend some shampoo at the pet supply store. BTW you are not the dog's mother.

They have this spray it's called hot spot spray to stop the itching

You can always try a different vet.Quite often, itching can be due to allergies. Food allergies are pretty common, and other allergies can include fleas, pollen, grass, any number of things.If you want your dog to have a healthy skin and coat, you need to feed high quality dog food. That grocery store stuff is pure garbage. Evo, Blue Buffalo, and Orijin are all examples of high quality food. You end up feeding your dog smaller portions, so you aren't spending that much more money in the long run. A fish oil supplement should also help.In the meantime, he could use a good bath. Look for dog shampoo that is meant to soothe itchy skin. Make sure ALL of the shampoo is rinsed off, as any residue left on the skin will make him even more itchy. Being a mix, if he has more of a sheltie coat, he may have a lot of undercoat that needs to be brushed out properly. If his coat is super thick and getting matted, you may just want to bring him to the groomers for a bath. They will bathe and blow dry him.