My advice is do NOT clean out the ears for a day or two before the vet appointment. The vet needs to see the junk that's in the ear and be able to get a swab of it for the microscope. If you clean out the ear it makes it alot harder for the vet to find out what's causing the problem and which med is likely to work for it.

Also do not put any ointments, creams, washes, liquids or anything else in the ear. Those things can skew the results of any tests the vet may want to do.

As much as I know you'd like to be able to do something to help your dog in the meantime, anything you might do would only bring temporary relief at best and may cost more money at the vet if they have to repeat tests because of something you used, or your dog may have to wait several days for relief because of an interaction with the stuff you put in the ear not mixing with what the vet wants to use.

Best advice I can give you is just give your doggie extra loving and get him to the vet as soon as they can get you in.

I hope all goes well and the itching stops soon.