Many Labrador retrievers exhibit distinct nose pigmentation features that can often be puzzling to their owners. In most cases, the color of a Lab’s nose often reflects the color of its coat. This is particularly true with a chocolate Lab or black Lab. However, a yellow Lab often experiences a change in its nose pigmentation as it matures.
The parts of the body where pigmentation is most visible include the nose, gums, feet, tails, lips and the outer rims of the eyes. The most commonly observed colors include yellow brown (also referred to as “liver-colored), black, and brown.
The color of the Labrador retriever is influenced by many types of genes. Generations of breeding may result in appearance of unexpected pigmentation in different parts of the body which is brought about by recessive genes. Most of these pigment manifestations occur in yellow Labs although it has also been observed in chocolate Labs.
The genetic make-up of a Labrador retriever may include genes for a different coat color. Thus there are instances when a black Lab carry a recessive gene for the chocolate or yellow color and a yellow Lab can carry recessive genes for black or chocolate. The presence of these recessive genes can easily be revealed by DNA testing. It is for this reason that it is often difficult to control or correct nasal pigmentation by breeding. There have been attempts of crossbreeding but the efforts have not been successful in preventing the succeeding generations from carrying and manifesting the recessive genes.
The nose pigmentation of yellow labs is often caused by a gene which is distinct from the one which controls its coat color. The change in pigmentation is attributed to the amounts of the enzyme tyrosinase which are present in the body at specific seasons of the year or the age of the dog. Tyrosinase controls the production of melanin pigment which is responsible for the black pigment of a Lab’s nose and other parts of the body. Since tyrosinase is a temperature-dependent enzyme, during summer, dogs produce more tyrosinase to boost the melanin levels in the body which functions to protect the dog from the harmful ultraviolet rays of the sun. With more melanin, a yellow Lab’s nose will appear darker during the summer months. A yellow lab’s black nose has been observed to gradually turn pink as a part of the aging process. This condition is often referred to as “snow nose” or “winter nose”. The production of Tyrosinase also decreases as the dog ages. In order to protect a dog’s nose from sunburn or ultraviolet injury, the application of sunscreen has been advised.
Some of the common nasal depigmentation in Labrador retrievers includes the so-called “Dudley Nose”. These are yellow Labs which possess either pink noses, liver or chocolate noses, or “flesh-colored” noses. In most cases, the color of their noses is also manifested around the eye rims. The condition has also been viewed as a form of vitiligo. Depigmentation associated with a Dudley Nose primarily occurs on the hairless part of the skin of the nose. It should be noted though that complete depigmentation has not been noted. Some yellow Labs may experience a remission wherein depigmented nose becomes darker.
Under AKC’s standards, a yellow Lab can be called a true Dudley if the pigmentation of the nose is also manifested around the rims of its eyes. Breeding standards established for Labrador retrievers disqualifies a true Dudley from competing in conformation shows. However, true Dudleys are extremely uncommon.
Another form of nasal depigmentation is not a congenital condition rather it is a localized form which is attributed to a Lab eating out of plastic or rubber dishes that may contain the chemical p-benzyl-hydroquinone. This chemical has been demonstrated to be readily absorbed via the skin and inhibit the production the melanin pigment. The condition has been called Plastic Dish Nasal Dermatitis which is also manifested by the irritation and inflammation of the skin of the nose.
Most cases of nasal pigmentation are considered a fault rather than a disqualification. The absence of pigment on the nose of many Labrador retrievers is mainly a cosmetic problem but should not prevent a dog from competing in conformation shows.