Several factors can cause a dog's nose to turn pink, including temperature changes or nasal depigmentation, also known as "Dudley nose." Certain breeds are more affected by temperature or more prone to depigmentation than others.
A pink nose can be indicative of a serious medical problem, so if a pet owner is in doubt, a veterinarian should be called. "Winter nose" or "snow nose" affects many breeds, such as Labradors and terriers. Short and cold winter days turn a dog's black nose pinkish. The reason why this occurs is not known. The phenomenon of winter nose does not usually indicate a permanent loss of color.
Nasal depigmentation in dogs is a form of vitiligo. In some cases, a dog's black nose turns pink. In other cases, the color fades to a chocolate-colored brown. In either case, this is considered a cosmetic problem and does not typically require medical attention. Nasal depigmentation is most common in Afghan hounds, golden retrievers, Labrador retrievers, Irish setters and poodles, though it can occur in any breed.
Plastic dish dermatitis also affects some dogs, causing inflammation near the nose. In most cases, this painful condition is remedied by keeping a dog indoors and using only glass, stainless steel or ceramic bowls for food and water consumption.