A dog's skin changing color raises concern, but when the skin loses color, it can often be attributed to a harmless condition called vitiligo. Often seen around the lips, eyes, nose or genitals, vitiligo causes normally dark-pigmented skin to turn light or pinkish without any scales or bumps heralding infection.
How to Tell
Vitiligo occurs when the melanocytes in the skin are lost or no longer do their usual job of producing pigment. Dogs with vitiligo may develop white hairs scattered throughout their coat or get larger patches with loss of color. Friction on the mouth and nose -- such as that incurred while digging or chewing a bone -- can stimulate melanin loss in affected dogs. Injuries on dogs with vitiligo often heal with white hair growing over the site of the healed injury.
Getting a Diagnosis
When you notice areas of lost pigment on your dog, a visit to the vet will rule out more serious conditions. The vet scrapes a bit of skin from the site for testing to confirm the diagnosis and to rule out a skin infection or other disorder. He may draw blood or do other tests to rule out an underlying disorder such as hypothyroidism, uveodermatologic lymphoma or hormone imbalance that can cause changes in a dog's coat and skin color.
How Did This Happen?
Your dog's spotty appearance is usually not due to any fault of your own. The hereditary form of this condition is more common in akitas, dachshunds, Old English Sheepdogs and several other breeds. The non-hereditary form of the disease is usually caused by an autoimmune response affecting the melanocytes. Stress may trigger the onset of vitiligo, so examine your dog's lifestyle and behavior for anything triggering anxiety.
No medical treatment for vitiligo is available, nor is it necessary, as vitiligo is considered harmless. Your vet may recommend increasing your dog's outdoor time on sunny days, as UVB rays may stimulate melanocyte production and prevent new loss of pigment from developing. Although the disorder is not associated with nutritional deficiencies, consult with your vet about whether your dog's diet is providing sufficient nutrition for optimal immune system function. In extreme cases, if you choose, your vet can darken the lightened areas cosmetically with tattoo ink.