Home » Symptoms » Dog Symptoms A-Z » Loss of pigmentation on third eyelid margin

Loss of pigmentation on third eyelid margin in Dogs

Author: Dr. med. vet. Gisa Löwe | Last modified: 20.02.2026

When to visit the vet?

Home care monitor at home and contact your vet if worse

YELLOW/ORANGE if there is redness, discharge, rubbing/pain, corneal clouding, or vision problems. RED in case of acute severe eye pain or loss of vision.

Unsure about what’s wrong with your pet? Feel free to use our Symptom Checker for more clarity

Definition

A loss of pigmentation on the third eyelid margin in dogs is a change in the normally dark color of the pigment ring that surrounds the edge of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye.. This change may indicate various health problems, which can be both harmless and serious.

Can Occur with the Following Diseases:

Keratitis Pigmentosa (German Shepherd Keratitis, KSC, Pigmented Cornea)

Basics and possible causes

The nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye. is an additional, third eyelid structure in dogs that provides protectionProtection refers to safeguarding against diseases or harm. In veterinary medicine, this can include protecting animals through vaccinations, the use of parasite control products, or providing a safe environment. against foreign bodies and ensures even distribution of tear fluid. The black pigment margin serves as protectionProtection refers to safeguarding against diseases or harm. In veterinary medicine, this can include protecting animals through vaccinations, the use of parasite control products, or providing a safe environment. against UV radiation and prevents the penetrationPenetration describes the entry or permeation of a substance or organism into a body or material. In medicine, it can refer to the penetration of microorganisms into tissues or the insertion of instruments into the body. of light that could irritate the eyes. The pigmentation of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye. is determined by melaninMelanin is a pigment found in the skin, hair, and eyes of animals (including humans). It determines color and provides protection from UV radiation. Conditions affecting melanin production can lead to changes in coloration., a pigment that also affects skin and eye color.

A loss or change in pigmentation can be caused by a variety of factors. A common cause is chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. eye irritation or Inflammatory conditions triggered by allergies, infections, or Foreign body in the eye. ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Inflammatory conditions can damage the melanocytes, the melanin-producing cells, leading to a loss of pigment.

Autoimmune disease are another possible cause. In these diseases, the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. mistakenly attacks the body’s own structures, including the melanocytes in the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye.. Lupus erythematosus and Pemphigus foliaceus are examples of such diseases that can cause depigmentationDepigmentation is the process of pigment loss in the skin or hair, leading to whitish spots or areas..

Hormonal imbalances, especially those related to the thyroid gland, can also affect pigmentation. Hypothyroidism (underactive thyroid) can lead to Skin changes and coat changes, including pigmentation of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye..

Finally, genetic factors can play a role. Some breeds are more prone to depigmentedDepigmented describes areas of skin or hair that have lost their pigmentation and therefore appear lighter or white. In dogs and cats, this can be caused by genetic conditions, diseases, or skin injuries. areas, including the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye., due to their genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases..

Typical accompanying symptoms

Changes in eye color: A change in eye color or the irisThe iris is the colored part of the eye that surrounds the pupil. It consists of muscle tissue and adjusts the size of the pupil through its contraction or relaxation to regulate the amount of light that enters the eye. may indicate underlying diseases that also affect the pigmentation of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye..
Tear flow: Excessive tear flow can be a sign of eye irritation or Inflammatory conditions that can affect the pigmentation of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye..
Redness or Swelling: A red or swollen nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye. may indicate an Inflammatory conditions that can lead to a change in pigmentation.
Itching or rubbing of the eyes: Dogs that constantly rub or scratch their eyes may suffer from conditions that lead to pigment changes.
General Skin changes: Changes in skin pigmentation or coat may indicate systemic diseases that also affect the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye..
Decreased appetite or lethargy: These general symptoms may indicate more serious systemic diseases that can also affect the eyes.

When to see a vet?

It is advisable to consult a veterinarian if the pigment loss of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye. is accompanied by other symptoms such as redness, Swelling, tear flow, or Behavioral changes. These symptoms may indicate serious eye problems or systemic diseases that require immediate attention.

If the pigment loss occurs suddenly or worsens rapidly, a veterinary examination should also be performed. A rapid loss of pigmentation may indicate acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. problems that need to be treated.

A visit to the veterinarian is also important if the dog shows signs of Pain, such as frequent blinking, squinting, or light sensitivity. These symptoms may indicate eye injuries or more serious diseases.

Finally, a veterinarian should be consulted if the dog suffers from systemic symptoms such as weight loss, fever or general weakness, as this could indicate an underlying systemic disease.

Symptom recognition for the pet owner and veterinary diagnostic procedure

It is important for pet owners to pay attention to changes in their dog’s eye color or structure. Regularly looking into the dog’s eyes can help to detect changes early. Pay attention to signs of redness, Swelling, or excessive tear flow.

The veterinarian will first perform a thorough examination of the eyes to determine whether it is a local eye disorder or a systemic problem. In doing so, he will look for signs of Inflammatory conditions, injuries, or infections.

In addition, the veterinarian may perform special tests to check the function of the thyroid gland or test for Autoimmune disease. These include blood tests that measure hormoneHormones are chemical messengers produced by endocrine glands and released into the bloodstream to affect specific cells or organs in the body. They regulate numerous bodily functions, including growth, metabolism, and reproduction. levels or the presence of autoantibodies.

In some cases, a biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. of the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye. may be necessary to determine the exact cause of the pigment loss. This is especially the case if an Autoimmune disease is suspected.

What the pet owner can do and professional therapy options

Until the veterinarian has determined the exact cause of the pigment loss, dog owners should make sure to keep their dog’s eyes clean and free of irritants. This can be done by gently cleaning the eyes with a sterile saline solution.

It is important to prevent the dog from rubbing or scratching its eyes, as this can make the situation worse. A protective collar can be helpful in some cases to prevent the dog from injuring itself.

If an allergic reaction or irritation is suspected, the veterinarian may recommend avoiding potential allergens that could be affecting the dog’s eyes.

In cases where a systemic disease is diagnosed, it is important to follow the veterinarian’s treatment plan closely to prevent the symptoms from worsening. This may include administering medication or adjusting the diet.

Regular check-ups with the veterinarian are crucial to monitor the progress of the treatment and to ensure that no further complications occur.

Outlook on current research

The pigment loss on the third eyelid, also known as the nictitating membraneThe nictitating membrane, also called the third eyelid, is a protective membrane in the inner corner of the eye in dogs and cats. It provides additional protection and moistening of the eye., is a symptom commonly found in dogs. Current research is increasingly investigating the extent to which this pigment loss is related to genetic factors. Scientists have begun to identify genetic markers that may be responsible for the susceptibility of certain breeds to pigment changes. These studies aim to identify breeds that are at higher risk for pigment changes due to their genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases..

Another area of research focuses on the role of environmental factors in pigment loss on the third eyelid. It is being investigated whether factors such as UV radiation, diet and Contact with certain chemicals can contribute to depigmentationDepigmentation is the process of pigment loss in the skin or hair, leading to whitish spots or areas.. These studies are crucial to developing preventive measures that could reduce the risk of such pigment changes in dogs.

The connection between systemic diseases and pigment changes on the third eyelid is also being intensively researched. Researchers are trying to find out the extent to which changes in the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. or hormonal imbalances can lead to pigment loss. These studies could help to gain a better understanding of the complex interactions between systemic health conditions and local symptoms such as pigment loss in the eye.

Another exciting research approach is the investigation of the microbiota of the eye and its possible role in pigment loss. Researchers are analyzing how the bacterial balance on the surface of the eye could be related to pigment changes. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. studies suggest that a disturbed microbiota could increase the risk of pigment changes and other eye problems, which may lead to new therapeutic approaches.

The development of new imaging techniques for the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of pigment changes on the third eyelid is also an active area of research. Advances in technology allow veterinarians to obtain more detailed images of the eye structure in order to detect more subtle changes. In the future, these technologies could enable earlier and more accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of pigment loss and the underlying causes.

Research into the therapeutic treatment of pigment loss on the third eyelid aims to develop effective treatment methods that can reverse or stabilize pigment loss. These include both drug-based approaches and surgical procedures aimed at restoring the structure and function of the third eyelid.

Another area of research is investigating the psychologicalPsychological refers to anything related to the mind or behavior. In veterinary medicine, this can include the study of animal behavior, including stress responses and behavioral disorders. effects of pigment loss on the affected dog and its Behavior changes. Studies aim to determine whether the loss of pigments on the third eyelid is associated with stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. or discomfort for the dog, and how this might affect the animal’s behavior. These findings could help to develop more comprehensive treatment approaches that take the well-being of the animal into account.

In summary, research into pigment loss on the third eyelid in dogs is a dynamic and evolving field that aims to better understand both the causes and the effects of this symptom. The insights gained could lead to new diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment methods in the future that help to improve the well-being of affected dogs.

Frequently asked questions

1. What does it mean if the black pigment margin on my dog's third eyelid fades?

It means that the normally dark pigment on the third eyelid, also called the nictitating membrane, loses color. This can be due to a variety of factors, including genetic predisposition, aging, or underlying health problems.

2. Is pigment loss on the third eyelid dangerous for my dog?

The pigment loss itself is usually not dangerous, but it can be an indication of other health problems. It is important to determine the cause of the pigment loss in order to rule out possible underlying diseases.

3. Which dog breeds are most often affected by pigment loss on the third eyelid?

Some breeds, such as Labrador Retrievers, Golden Retrievers, and Dachshunds, show a higher susceptibility to pigment changes on the third eyelid. This is often attributed to genetic factors.

4. Can the pigment loss on the third eyelid be regained?

In some cases, the pigment can be partially or completely restored by treating or changing the dog's living conditions. However, it depends heavily on the underlying cause.

5. Should I take my dog to the vet if I notice pigment loss on the third eyelid?

Yes, it is advisable to consult a veterinarian to determine the cause of the pigment loss and to ensure that there are no serious health problems.

6. Can environmental factors influence pigment loss on the third eyelid?

Yes, environmental factors such as UV radiation, diet, and chemical exposure can affect pigment loss. A healthy lifestyle and protection from excessive sun exposure can be helpful.

7. Are there treatments for pigment loss on the third eyelid?

The treatment depends on the cause. In some cases, supplements, topical medications, or surgical procedures may be considered. The veterinarian can recommend the best treatment option.

8. Can pigment loss on the third eyelid cause pain or discomfort?

The pigment loss itself usually does not cause any Pain. However, if other symptoms such as redness or Inflammatory conditions occur, this could indicate an underlying problem that needs to be treated.

9. How can I prevent pigment loss on my dog's third eyelid?

While genetic factors cannot be changed, measures such as a balanced diet, adequate UV protection, and regular veterinary examinations can help minimize the risk.

10. Why is my dog's third eyelid important?

The third eyelid plays an important role in protecting the eye by acting as an additional barrier against dirt and foreign bodies and distributing tear fluid evenly over the eye surface.