Nose, Paw Pad, Lip and Eye Rim Color
Nose, paw pad, lip and eye rim color (pigment) is determined by genes that are separate from, but closely associated to, the genes that create coat color.
Nose color is very useful to determine the correct color of the dog, but most importantly the darker pigments protect the dogs nose from sunburn and skin cancer caused by exposure to UV rays.
Nose color can be seen at birth or within a few days after birth. Black, brown, gray, graybrown and merle Mudi puppies are typically born with fully colored noses. White and yellow pups noses usually begin a few days after birth to "color up". Albino's noses (lips, etc.) never develop any color other than pink.
Loss of nose color later in the dogs life is mostly due to vitiligo, snow/winter nose, and plastic dish nasal dermatitis:
- Vitiligo causes black pigment in the nose and sometimes the lips to fade to brown (the depigmentation is somewhat symmetric and can occur on other areas of the face, paw pads and coat can sometimes also be affected).
- Snow/winter nose causes the nose to fade to pale brown in winter, normal color returns as summer approaches. Snow nose occurs mainly in white and yellow coated breeds. The color change can become permanent in older dogs. It is not associated with any disease.
- Plastic dish dermatitis can occur if the dog eats or drinks out of plastic or rubber bowls. It is triggered by a reaction to an antioxidant found in the dishes.
Black Tongue Spots
Dogs can have colored spots on their tongue or anywhere in their mouth, just as they have spots on other parts of their body. These are the equivalent of freckles in humans. Black, ash/gray, white and yellow dogs usually have black tongue spots and brown dogs usually have brown spots. However any newly developed tongue spots should be shown to a veterinarian to determine their cause.
Websites for more information:
Butterfly Nose
Butterfly nose is a partially unpigmented nose, that usually occurs on dogs with white markings around the nose that occur from the white spotting gene that makes trim such as blazes on the face. (Butterfly nose does not usually occur on dogs that have solid white coats due to other genes and on those dogs that also lack white markings.) It is characterized by spotty areas of dark pigment and pink pigment. The pink areas are prone to sunburn and should have sunscreen applied to the nose depending on the sunlight conditions the dog will be exposed to. The butterfly nose is not a common occurence in the Mudi at this time due to the lack of white trim genes carried in the breed. Some puppies may be born with spotted noses but these will typically color up by a few weeks to months of age. The exact mode of inheritance is unknown, but butterfly noses do tend to be more common in those breeds whose lines are selected for maximal white face markings.
Snow/Winter Nose
The intensity of black pigment is controlled by a separate gene independent of the fur coloring. White and yellow Mudis usually have black noses, which may gradually turn brownish-tan with age (called "snow nose" or "winter nose"). This is due to a reduction in the enzyme tyrosinase which indirectly controls the production of melanin, a dark coloring. Tyrosinase is temperature dependent, consequently lighter nose coloration can be seasonal, due to cold weather. Additionally, less tyrosinase is produced after the age of two years. As a result, the nose color of most white and yellow Mudis becomes a somewhat brownish-tan shade as they grow older.
Website links with nose pigment information:
Dudley Nose
Dudley nose is a nose that has not colored up properly from birth, it is solid pink and not spotty. The paw pads, lip and eye rims may or may not have pigment, but in most cases they are missing as well. It is not a brown or tan nose on a white or yellow coated dog. It is not an albino either as the eyes are not blue or white. It is not the same thing as snow/winter nose as this nose never darkens again. Dudley nose is very rare and requires sunscreen to prevent sunburn. The cause is unknown, but it may be a form of vitiligo.
