My dog keeps scratching hot spots

I've had good experiences with food supplement oils you can mix into the food. Our dog liked it so much she would lick it directly out of the bottle. Ask your vet for a dietary supplement for skin and fur problems.

A natural supplement is an egg. Mix one raw egg into the food up to twice a week. It makes the fur very shiny and soft, but I'm not entirely sure how much it helps against itchy skin.

You can also apply oils on the rashes like a cream. Most itching is caused either by an allergy or by a lack of moisture. Oil will keep the skin moisturized naturally. Argan oil is traded as the "best oil in the world" (which I can confirm). It's save to eat and softens the skin if applied externally. You can use less expensive oils, but make sure they're safe to be eaten by a dog.