Oops! Should have written "Norwich Terrier" or "Norfolk Terrier". Such a terrier freak I forget other people don't know the breeds :P Check out some pictures of these breeds and see if that's the color of fur you have.
I've seen a number of Westies with brown around their mouths and paws. Some people are diligent about keeping their Westies "white", but the ones that play in the yard a lot tend to get discolored. There is another possibility as well. Westies are originally derived from either Norwich or Norfolk (I forget which came first), which are brown to red brown. Over time they bred the lighter coats into a separate breed. Westies are always supposed to be pure white, but it's possible you got one with a little ancestral coloring.
He has it around his mouth and on his chest because, like his feet, these are areas that are frequently exposed to his saliva. Naturally, as he is licking his paws, the hair around his mouth gets wet with saliva as well. Also as he is licking his paws, his head is bent down and the saliva-moistened "beard" hair touches his chest hair, depositing saliva there as well. Any area that comes into frequent contact with his saliva will be brown.
I am sorry it has took me so long to reply,Yeah the brown is a redish brown also he has it around his mouth and bits on his chest too.
He does bite and lick his paws alot but it doesn't explain why he has it around his mouth and chest.
I can't add much here, as Ghilly said some interesting things about the possible allergy problem.
But -just a thought...if it is the actual fur on his feet which is turning brown, could it be some kind of staining from where he habitually walks? If he walks a lot in grass or on earth which is brown or reddish brown, there are indelible pigments in those things which could cause a kind of 'permanent-dyeing' of his white fur...(?)
Ancient people used minerals from rocks as paint which remains on cave walls to this time!
I was wondering that because the other day I was walking with my dog and we were in a woods where the earth is reddish-brown. A white dog we met had brown fur around his paws. The lady with him said she could not get the stain out as she walks him there every day.
I know you have not yet responded to my questions, but I'm getting ready to go to work and won't be home until 11 tonight, so I wanted to toss this out there for your consideration before I go.
A manifestation of an allergy that affects a part of the body that does not come into direct contact with the allergen itself is called atopy. When a white dog's feet turn reddish brown, most of the time it is caused by an allergic reaction to something. The coloration itself is not caused by the allergy, it's caused by the saliva being deposited on the paws during the constant licking. The allergies are often to something in their dog food. Wheat and wheat gluten is a common allergen. Yeast infections between the toes causes an itching, which causes them to lick a lot, leaving saliva on the paws.
If it's a yeast infection of the paws, an antibiotic should help. If it's a food allergy, switching to a food without grain in it may help. As far as removing the brown, there are products that they sell to remove the brown tear stains from the eyes of white dogs. One of these may work. Otherwise, once the dog stops licking, eventually, over time, the brown hair should keep getting lighter and lighter until it's white again.
If she doesn't lick at her feet a lot, hopefully by the time I get home later you will have seen my posts and I will see whatever else has been added as far as what the dog is doing that could possibly be contributing to this. We have lots of members who have lots of good ideas. Hopefully, one of them will also chime in with some possibilities.
I'm going to need a bit more information. Where is the brown on his paws? Is it on the tops of the paws or on the walking surface? Does he lick at his feet a lot?