First aid

Pale Mucus Membranes in Dogs

Mercè Garcia
By Mercè Garcia. June 17, 2022
Pale Mucus Membranes in Dogs

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It is very important we take note of the color of a dog's mucus membranes. Similar to how changes in the eye can point to systemic health problems, when the dog's mucus membranes become pale or discolored it can mean they are suffering from a medical issue. The mucus membranes are transition tissues between the dermis and internal tissues. They are highly vascularized, one of the reasons they are more susceptible to color changes. They are also only on certain parts of the dog's body, meaning we often have to actively look for them to see any changes.

At AnimalWised, we look at pale mucus membranes in dogs. We understand what dog mucus membrane discoloration can mean, as well as provide some other symptoms to take into account. If you see any changes to your dog's mucus membrane coloration, it is important to seek veterinary diagnosis.

  1. Where are the mucus membranes of dogs?
  2. Pale mucus membranes in dogs
  3. Red mucus membranes in dogs
  4. Blue mucus membranes in dogs
  5. Icteric mucosa
  6. What to do if our dog has mucus membrane discoloration

Where are the mucus membranes of dogs?

Dogs have mucus membranes throughout their internal bodies. They are important for various purposes such as lining the gastrointestinal tract to absorb nutrients for metabolism. In terms of mucus membranes which can be visible to caregivers, we can observe them in three places on a dog:

  1. Gums and oral cavity: we can see the gums by lifting the dog's upper lip and looking into their mouths. It is important to note that some dogs have darker mucus membranes in their mouths due to natural pigmentation. We can still observe changes to their coloration, but they are often more difficult to detect.
  2. Internal side of the eyelids: we can make an inversion of the eyelid with our thumb, although this should be avoided in case we introduce bacteria to the eye. As with the gums, the inner face of the eyelid can be dark in color.
  3. Genitals: the glans penis in males can be exteriorized or the vulvar fold in females inverted. If you do not have experience it can be somewhat complicated to do.

We can know that the mucus membranes of a dog are normal when we observe them as pink, moist and shiny. They should have a capillary refill time (CRT) of no more than two seconds. Mucus membranes that are dry or show abnormal CRT suggest an abnormality in the peripheral circulation and may be caused by shock or dehydration of the dog.

Capillary refill time (CRT)

The capillary refill time is the time elapsed between capillaries being drained via compression and then being refilled again. This can be carried out on various parts of the skin. It is easier to perform on humans as we have much of our skin exposed. In dogs, the hair which covers their body can make this difficult. For this reason, the mucus membranes are often the best place to carry it out since we can see them more easily.

Calculating the capillary refill time is very simple, we only need to press our finger on the mucosa (genital or oral), which will turn white. After two seconds it should return to the pink color. In the case of observing mucosa of an abnormal color, it is always advisable to assess a second mucosa. In doing so, we will be able to detect a possible local or generalized variation.

Pale Mucus Membranes in Dogs - Where are the mucus membranes of dogs?

Pale mucus membranes in dogs

When we look at the mucus membranes and see they are pale it means there is either a decrease in blood flow or red blood cells. It is common in dogs that are in a state of shock, dogs that suffer from internal bleeding or those that have suffered from poisoning. In these cases, the dog is undergoing a medical emergency. If the mucus membranes are completely white, they are in trouble.

In an emergency veterinary situation, a vet will look at the mucus membranes of the dog when assessing them. If they are very pale or white, it is likely the dog will be in a serious medical condition.

Pale Mucus Membranes in Dogs - Pale mucus membranes in dogs

Red mucus membranes in dogs

When we observe the mucus membranes pf a dog are of an intense red color, it means they are congested. They indicate an increase in blood flow and the cause of this color may be related to heat stroke in dogs or blood infections such as sepsis. Sepsis is a life-threatening condition and the dog will need to be stabilized in a veterinary clinic.

Learn more in our article on sepsis in dogs.

Pale Mucus Membranes in Dogs - Red mucus membranes in dogs

Blue mucus membranes in dogs

We can observe the blue or violet mucus membranes when they have cyanosis. This is an increased concentration of reduced hemoglobin (Hb), indicating a lack of oxygen in the blood. Clinically evident cyanosis typically occurs at an oxygen saturation of 85% or less[1]. It can be caused by suffocation or poisoning.

Learn more with our article on poisoning in dogs.

Pale Mucus Membranes in Dogs - Blue mucus membranes in dogs

Icteric mucosa

We can observe yellow mucus membranes. It indicates an increase in bilirubin values and can be caused by many causes, ranging from intoxication to hemolysis. This discoloration is often related to liver and kidney functioning. When these organs cannot function, they cannot filter the toxic substances which pass through the body. The result is their accumulation, which can result in jaundice in dogs, amount other issues.

Read our related article on why your dog's skin is turning yellow to learn more.

Pale Mucus Membranes in Dogs - Icteric mucosa

What to do if our dog has mucus membrane discoloration

If we observe congestive or cyanotic mucus membranes, we must go to the vet immediately, since it is a veterinary emergency. However, the other colorations are no less important, we will call our trusted veterinarian to communicate the situation and see what measures to take.

In many cases, the treatment options will be required to slow down the damage caused by different types of liver failure in dogs or other issues. This may mean that some damage has occurred and we need to focus on preventing more damage and managing ongoing symptoms. We will also need to look at any concurrent symptoms to help inform the veterinarian and carry out an accurate diagnosis.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Pale Mucus Membranes in Dogs, we recommend you visit our First aid category.


1. Heinzman, D. M. (2007). Chapter 30 - Cyanosis. In L. B. Zaoutis & V. W. Chiang (Eds.), Comprehensive Pediatric Hospital Medicine (pp. 145-148).

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Pale Mucus Membranes in Dogs