Get Your Dog Care Questions Answered by Experts
It CAN be a sign of a thyroid condition or an immune disorder BUT it's usually something much more simple.
Some dogs get sunburned or their noses get dry and brittle and peel because of the weather. Your dog might have also suffered a trauma to the nose and the skin was peeled off. This can happen in fights with cats or wild animals.
I suggest you place sunscreen on it every day until the color returns to normal. This pink skin is very succeptible to sunburn. You should also keep it well moisturized.
If you don't see it start to resolve within the first week or so, you will want to see the vet to rule out a bigger problem.
Let me know if still have questions.