Dogs sometimes encounter nose color changes due to conditions, such as nasal depigmentation or plastic dish nasal dermatitis. Nose color changes can also indicate that the dog is suffering from a nutritional deficiency, is infected with parasites or is undergoing hormonal changes.
If a dog's nose changes color, then the dog should be brought into the veterinarian's office as soon as possible. The problem with the nose color change is that it can indicate that there is a small and easily solved problem with the dog or that there is a severe and life-threatening problem. The reason for the color change cannot be determined based on the color alone and requires tissue smears, blood work and possibly bacterial cultures or allergy testing in order to determine the exact cause.