Hi there,
Here are my offerings.
I personally would go back to the vet medication will bridge time until you try some of the following to get on top of it.
Do not bath him in anything but Hibiscrub or Malaseb preferably the Hibiscrub.
Thornit powder will help his ears it is avaliable from here
http://www.championpets.freeserve.co.uk/ears.htmCarpets can cause a lot of problems as they are dusty, My bitch westie gets itchy on the carpets so she does not get on the carpeted area which luckily for me is basically upstairs, Kitchen, Lounge, Diner, etc are all tiled or wooden floored.
All bedding should be washed every couple of days with a mild non Bio such as fairy washing powder temp at least 60 degrees
Try him on a more natural diet, IMHO westies DO NOT benefit from Complete diets. Seearch the net for BARF and RAW diets, alternatively try AMP/Prize choice products avaliable from most large pet shops they are also very good. Very good book that is easy to follow and is inexpensive is natural nutrition for dogs and cats THE ULTIMATE DIET by Kymythy R.Schultze it is available from
http://www.caninenaturalcures.co.uk/books2.htmlAloe vera, apple cider vinegar in his water but just a littler of the ACV. Omaga fish oils, evening primrose oil are all very good supplements.
This won't cure him over night but it is at least a start. Could you find a homeopathic practitioner near you.
Pam