Loss of Pigement Around Face

Question
I have a male fawn boxer that approximately 5 years old.  He is active and I walk him daily.  In October 2012 I had to board him for about a wek and upon picking him up he looked as though he had gotten contact dermatitis, nose was pink not black as before, eyes lids were inflamed and heis muzzle was whitish/ grey.  I though he may have had some allergic reaction but it has not changed over the months and his personality appears to demonstrate anxiety.

Is this a phase he is going through or a disease process?  I've had his vet look at him but had no explanation.  I would appreciate your input.

Answer
I've never heard of this, however, if he was boarded at a vet's boarding- the vet is responsible for this.

There is no excuse for a vet having no explanation- contact the owner of the boarding facility- or the vet- demad answers- get tests- get a new vet that will give answers and treatment.

Someone is responsible for this.