It's possible that these dry brown scales on your dog's nose are the result of too much sun exposure, contact with an irritating substance, or an allergic reaction to something either contacted, in the environment or ingredients in his food.http://www.sniksnak.com/doghealth/allergies.html
It will be necessary to have your dog evaluated in person by his vet, to determine the cause of these scales and then have them treated, after diagnosis. The vet may want to do a skin scraping (painless) to view the composition of the scales and obtain more information for a definite diagnosis, so the best treatment can be prescribed.
If your regular vet cannot make a diagnosis, a referral to a veterinary dermatology specialist would be a good next step. You can find names of dermatolgy specialists, here: www.acvd.org
For the moment, continue to keep the area clean, as you have been, and monitor him for any changes in the appearance of these scales, until you can get him assessed in person by the vet.
I hope all will be well with your dog!
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