White vs White

Two very different mechanisms can cause a solid white coat in dogs.

So… what’s the difference? Some dogs have a pigmented coat, but with a very pale pigment color. And the others appear white because they don’t produce any pigment at all.

Both, low pigment intensity and extreme white can produce a fully white coat. And these phenoytpes can be hard to tell apart for beginners.

The main difference for breeding purposes is that a very, very light blonde dog still has pigment and is not at risk for health problems. In comparison, the extreme pigment deficiency in dogs without pigment can lead to blue eyes or a lack of skin and nose pigment. As well as putting them at risk of hearing impairment.

Low Red Intensity

Many dog breeds are solid white or at least have a solid white variety.

Just think of a white Samoyed, Spitz, Bichon, Westie, Great Pyrenees, Swiss Shepherd, or Poodle.

White Coat Dogs white phaeomelanin Poodle

White Coat Dogs white phaeomelanin Spitz

These breeds are recessive red (e/e) with a low phaeomelanin intensity.

This is the same pattern you can see in yellow Labs or apricot Poodles.

These dogs can only express phaeomelanin (red pigment) in their coat.

The only difference is that the amount of phaeomelanin in these lighter dogs is so low that they appear white. Some testing companies call it the “dilution” of red pigment.

White Coat Dogs poodle example red — Same pattern, just different shades of red pigment

White Coat Dogs poodle example apricot — Same pattern, just different shades of red pigment

Red intensity is controlled by multiple genes, not all of them well understood.

By default, phaeomelanin is a yellow or red pigment.

But there are modifiers at play that can change an individual dog’s phaeomelanin density. This causes a gradient from rich red to yellow to cream or white colors.

The thing is that selective breeding can affect the shade of phaeomelanin.

You might remember the trend to breed Golden Retrievers with a lighter and lighter coat until they looked white instead of the golden color that gave them their name?

Most breed standards define a preferred range of phaeomelanin colors for each breed.

For example, Irish Setters only come in mahogany or chestnut red, Vizslas are a rusty color, yellow Labradors are golden, and Bichons are typically solid white.

There are a number of breeds that only come with white phaeomelanin, never red or yellow. This covers almost all of the dog breeds that only accept solid white.

Interestingly, very pale phaeomelanin is mostly found in dog breeds that are recessive red (e/e).

Most patterned dogs have yellow or orange phaeomelanin

There are also some breeds (e.g. Akita Inus or Shibas), where patterned dogs have tan or orange pigment. However, in their recessive red puppies, the phaeomelanin is diluted to white.

So the shade of the phaeomelanin can be linked to the pattern of a dog. Neat, isn’t it?

The working theory is that some untestable modifier may only affect dogs with this pattern and make them appear lighter.

White Coat Dogs pattern related red intensity — Shiba Inu Puppies

Dogs with low pigment intensity are not at risk for hearing loss. They also don’t get blue eyes from their color pattern. Their pigment distribution is not disrupted.

Just think of them as very pale blonde dogs.

Extreme White

Some dog breeds that come in white have extended white spotting patterns.

Everyone knows dogs with some white markings, yes?

These dogs express traits that cause a lack of working pigment cells in some areas of their coat.

And with the help of some unknown modifiers, these white markings can get so large that they cover the whole dog. This is what happens in dogs with a white coat that truly lacks pigment.

Breeds and varieties with a fully white coat from a lack of pigment include white Bullterriers, Frenchies, American Bulldog, Dogo Argentino as well as Dalmatians, English Setters, or Australian Cattle Dogs (the latter breeds are also born white, just with ticking or roan starting to fill in white areas later).

White Coat Dogs extended white spotting American Bulldog

White Coat Dogs extended white spotting French Bulldog

The most common things that can cause a lot of white are very extended piebald spotting (S locus) or very extended whitehead spotting (untestable).

Piebald patterns remove pigment starting from the lower part of the dog’s body.

Whitehead, on the other hand, begins to remove pigment on a dog’s front and face first.

The amount of white from piebald or whitehead seems to be controlled by unknown modifiers.

White Coat Dogs whitehead trait — piebald

Dogs can express both traits, piebald, and whitehead, at the same time. So the white can add up. Many high-white breeds express both traits, e.g. Russell-type terriers, English Bulldogs, or American Bulldogs.

White Coat Dogs extended white spotting example JRT 2

White Coat Dogs extended white spotting example JRT 3

Unfortunately, whatever disturbs the journey of pigment cells into the coat can also affect the ears and eyes. This is why breeds with lots of head-white are at a slightly greater risk for deafness.

Dogs with white faces also often have blue eyes or pink spots in their nose pigment or eye rims.

White Coat Dogs extended white spotting blue eye

White Coat Dogs extended white spotting missing skin nose pigment pink

Low Intensity vs. Spotting

How to know if a dog has white pigment or no pigment?

Well, it is not always possible without genetic testing.

But there are some telltale signs that give away which of the two white-causing things a dog might have:

Dogs with a recessive red pattern (e/e) and pale white phaeomelanin tend to still have some light traces of color, usually some buff or cream color around their ears and back.

Ear shading can be very pronounced or very faint.

Another thing that happens very often in these dogs, is nose pigment fading.

White Coat Dogs white phaeomelanin ear shading

White Coat Dogs white phaeomelanin Great Pyrenees snow nose

Only real white spotting comes with clearly defined patches of color or ticking/roan against a white background. If a dog has even minor mottling on his ears or some freckles on his muzzle, you know he has to have a truly white coat (in this area of his body, at least).

Just keep in mind that you can often see skin spots in these dogs. This is not the same as ticking.

Other signs of real white spotting are one or two blue eyes (which can also be caused by other traits) and a full or partial lack of pigment on the nose, lips or eye rims. Not a pale hypopigmenetd nose, but real pink spots.

White Coat Dogs extended white spotting ear dots

White Coat Dogs extended white spotting ticking blaze

To make matters a little more complicated, many white dog breeds come with both traits (white pigment and white markings) at the same time. You can’t really see or select against white spotting if the dog is already white from having white pigment…

In fact, the majority of American Eskimo Dogs, Bichon Frise, Bolognese, Maltese, Maremma Sheepdogs, Coton de Tulear, Samoyeds, or Great Pyrenees test positive for piebald spotting.

If their pigment is not super pale, you can sometimes see a faint spotting pattern!

White Coat Dogs piebald Samoyed — *Samoyed with cream patches*

Last but not least:

There is one thing that both traits have in common…

They can both hide any pattern a dog would otherwise have expressed!

If a dog can either only produce phaeomelanin (white, yellow, or red, doesn’t matter) or can not produce any type of pigment at all (white), most of its true pattern will be invisible from the outside.

A white dog always has a hidden or masked pattern underneath its white coat.

Did you know that most Dogo Argentinos are brindle sable with a black mask hidden by their white spotting? That Samoyeds would mostly be black & white patterned? Or that most Maltese would have a black & tan pattern if only they could make black pigment?^[1]

Unfortunately, both recessive red and white markings can also cause a “hidden Merle” situation.

A Merle dog can’t express its pattern if it doesn’t have eumelanin (black pigment) in its coat. So you can’t see if a white dog is also Merle. That is why it’s super important to test breeding dogs when meddling with Merle.

Other Traits

To other things come to mind that can cause white coat in dogs:

Domino restricts eumelanin production. And it can lighten phaeomelanin. If you combine it with a sable pattern (k^y/k^y A^y/ e^G/-), it can remove black hair tips and cause a very off-white coat. If you spot a very pale sighthound or Husky, it might be a sable domino.
Double Merle describes a phenotype where a combination of two longer merle alleles (e.g. Mh/M or M/M) delete pigment to white instead of just merling it. In severe cases, this can cause a mostly white coat.
Albinism is a rare genetic condition that affects the production of melanin. Dogs with albinism often have white to very pale creamish coats but they also lack nose, skin, and eye pigment which sets them apart from dogs with just a white coat.