Diagnosis

• It is difficult for a veterinarian to diagnose a dog's condition based only on the appearance of the nose. Consequently, a veterinarian may order a battery of tests, including blood work, evaluations of scrapes or smears of tissue samples, fungal and bacterial cultures, a biopsy and possibly even allergy testing, says Michael Abdella, a practicing veterinarian in Laguna Hills, CA, who offers advice on Dog Channel.
  
  

Considerations

• At times, a dog's nose may appear normal other than turning tan, pink or a lighter color. This permanent depigmentation does not appear to be related to any underlying conditions. When this happens, affected dogs are known to have "Dudley noses." Though there is no documentation of the successful treatment of this condition, it is not considered harmful, says Mike Richards, a practicing veterinarian in rural Virginia, in an article for Vet Info.
  
  

Effects

• Dogs can lose pigment in their nose as a result of the effect of winter weather, which is why the condition is referred to as "winter nose" or ''snow nose.'' It is not known whether this condition is due to reduced sunlight or thermal changes. There are no reports of successful treatments for this condition, though some believe artificial sunlight lamps can help. Some veterinarians also recommend giving your dog vitamin E (400 I.U. per day), according to Richards.
  
  

Expert Insight

• Some dogs may develop contact allergies to plastic bowls, which can cause skin irritation and depigmentation. If this is the case, invest in stainless steel or ceramic food bowls. Vitiligo is another condition known to cause depigmentation of patches of skin and the growth of patches of white hair. Other causes can include pemphigus, an immune mediated disorder, and hypothyroidism, according to Richards.
  
  

Warning

• If your dog's nose is changing color, take her to the veterinarian, since it could be caused by severe conditions such as nasal tumors. Indeed, squamous cell carcinomas can appear on the noses of dogs, especially those with a light coat who are exposed to high levels of sunlight and UV radiation, according to Jon Geller, another veterinarian who offers advice on Dog Channel.