It’s not unusual for a dog’s coat color to change as they grow older. However, a dramatic change from white to black fur can be concerning for some dog owners. There are a few possible reasons why your dog’s fur may be changing color.
Genetics
Genetics play a major role in determining a dog’s coat color. Many breeds experience lightening or darkening of their fur over time due to genetic factors. For example, puppies are often born with darker fur that lightens to a more silver or white shade as they mature. The opposite can also happen, where dogs begin developing more prominent black fur as they age.
Certain breeds are predisposed to changes in pigmentation due to their genetic makeup. Dogs with the ‘agouti’ gene, such as German Shepherds and Poodles, commonly develop darker fur pigmentation over time. The silvering or greying gene in dogs like Schnauzers causes a loss of pigment and whitening of the fur over time. Environmental factors can interact with genetics to speed up or alter these natural color changes.
Sun Bleaching
Exposure to sunlight can cause bleaching or lightening of your dog’s fur over time. The sun’s ultraviolet rays break down pigments in the fur, removing color. Some areas such as the muzzle, ears, back, and stomach are more prone to sun bleaching because they receive more sun exposure. A lack of pigment in newly regrown hair can leave your dog with patches of white fur after periods of sunbathing.
Vitiligo
Vitiligo is a condition that causes depigmentation and whitening of areas of skin and fur. It occurs when melanocytes, the cells responsible for pigment production, are destroyed. This can happen as an autoimmune response or due to factors like stress, trauma, or sun overexposure. The fur of affected areas turns white due to a lack of melanin pigment. Vitiligo usually starts with small patches of white and slowly spreads over time.
Cushing’s Disease
Cushing’s disease is a hormonal disorder that can cause fur color changes in dogs. It occurs when the adrenal glands produce too much cortisol. Darkening of the skin and fur is one symptom of Cushing’s along with hair loss, thin skin, excessive panting and water intake. The high cortisol causes an increase in skin pigmentation. As the disease progresses, your dog may develop patches of darker fur across its body.
Follicular Dysplasia
Follicular dysplasia is a hereditary condition in dogs causing abnormal hair follicle development. It can lead to sparse, brittle hair and bald patches on the body. The skin in affected areas lacks pigmentation and appears pale. Regrowth of dark fur is inhibited in those spots, leaving white or pink skin exposed. Slowly the pale patches tend to merge and spread, replacing the normal colored fur.
Alopecia Areata
Alopecia areata causes round bald patches on a dog’s body where hair suddenly falls out. It’s an autoimmune disease that attacks the hair follicles. The skin in these bald spots lacks pigmentation, appearing pink or white compared to surrounding fur. If the hair regrows, it may lack melanin and come back in white. Over time, more patches of depigmented fur may appear across the body.
Skin Conditions
Certain skin conditions like vitiligo, follicular dysplasia and alopecia areata can cause pigment loss and whitening of the fur. But other problems like infections, allergies, hormonal disorders and trauma can also damage the skin and inhibit pigment production in those areas. Any condition leading to recurring skin inflammation, lesions or scarring has the potential to disrupt melanin distribution and cause white patches.
Canine Leukocyte Adhesion Deficiency
Canine leukocyte adhesion deficiency (CLAD) affects the body’s ability to fight infection. Dogs with CLAD lack important proteins that allow immune cells to move into tissues. One symptom is abnormal pigmentation. White spots and patches develop on skin prone to trauma or infection due to improper healing and scarring. Over time these depigmented spots may spread across the body.
Testing Options
To determine the cause of fur color changes, the following diagnostic tests may be recommended:
- Biopsy – Microscopic examination of skin samples to assess pigmentation cells and rule out conditions like vitiligo.
- Culture/cytology – Testing samples for bacteria, yeast and mites.
- Bloodwork – Checking hormone levels and immune function.
- DNA tests – Identifying genes associated with coat colors and pigment disorders.
- Skin scrapings – Looking for parasite eggs which can cause irritation.
Medical Treatments
Treatment will depend on the underlying cause. Some options include:
- Steroids and immunotherapy for alopecia areata and follicular dysplasia.
- Antibiotics, antifungals and medicated shampoos for skin infections.
- Melanocyte-stimulating hormone injections to restore pigment.
- Medication to regulate hormone disorders like Cushing’s disease.
- Immunomodulatory drugs for autoimmune vitiligo.
- Nutritional supplements to support skin health.
Home Care
In addition to medical treatment, the following home care can be helpful:
- Use dog-safe sunscreen on exposed skin prone to depigmentation.
- Keep the dog out of the sun during peak hours.
- Use a dog jacket or shirt for added sun protection outdoors.
- Ensure excellent nutrition with a high-quality diet.
- Supplement with vitamins E, C, zinc, copper, and omega oils.
- Brush frequently to remove dead hairs and improve circulation.
- Bathe with medicated or moisturizing shampoos as recommended.
Outlook
The outlook depends on the underlying cause. Skin pigment disorders like vitiligo and leucocyte adhesion deficiency may slowly progress over time. But conditions like Cushing’s disease, fungal infections, and trauma can potentially be resolved with proper treatment. In most cases, fur color changes don’t directly impact the dog’s health. However, monitoring for secondary skin infections is important. With supportive care, dogs can still live a full, happy life despite pigment-related fur changes.
Prevention
To help prevent fur color changes:
- Breed genetically diverse, healthy dogs.
- Avoid excessive sun exposure.
- Maintain proper nutrition and vitamin levels.
- Treat skin infections quickly.
- Reduce stress and trauma to the skin.
- Groom regularly to promote skin health.
- Use dog-safe sunscreens and protective clothing.
When to See the Vet
Contact your vet if your dog develops any unusual pigment changes. It’s important to identify or rule out any medical causes. You should also consult your vet if you notice:
- Significant hair loss, thinning, or balding areas
- Red, inflamed, or scaly skin lesions
- Itching, scratching or licking the affected areas
- Changes in appetite, activity or energy levels
Schedule an appointment as soon as you spot any concerning fur or skin changes in your dog. Early diagnosis and treatment can improve the outlook for many pigmentation disorders.
Conclusion
A white dog’s fur turning black can be puzzling and concerning. But coloring changes are not uncommon in many breeds. Vitiligo, sun exposure, Cushing’s disease, and other factors can cause pigment loss and fur depigmentation. However, darkening fur may also occur in some dogs as part of the normal aging process. It’s important to see your vet to diagnose the specific cause. Underlying medical conditions should be addressed. With proper care and treatment, dogs can still live a healthy life despite pigment-related fur changes.
