What are Depigmentation Disorders?
Depigmentation always refers to the loss of pigment or lightening of skin and hair. This is different than hyperpigmentation, which causes a darkening or brown and black coloring to appear on the skin. Some cats that lose pigment over time may become more susceptible to sunburns. Injury and scar tissue can lead to the loss of pigment in the hairs that regrow over the area. Depigmentation is the most obvious on black cats. Certain conditions such as leukoderma can create lace-like patterns of white across the cat's coat. Speckling, webbing or snow-like markings are also common. Some health issues may cause the nose alone to lose pigment. Assessment by a veterinarian is needed to determine if the depigmentation on a cat is harmless or if it is related to a serious health problem.
Other than the slight graying of a cat's coat over time from aging, the color of a cat's fur and skin should not change. There are a number of genetic conditions and acquired diseases that can cause pigment to be lost, leading to white or lightened areas of skin and hair on the cat. Any abnormal loss of pigment is referred to as “depigmentation”. Some cats may be born with varying degrees of depigmentation, but most cases become visible over a period of years.
Symptoms of Depigmentation Disorders in Cats
Cats who have depigmentation from a genetic disorder may only exhibit cosmetic symptoms. More adverse signs are often paired with underlying health issues. All symptoms to watch for include:
- Sections of white or lightened fur that increase in number over time
- Whitening of skin and fur around the eyes
- Tumors or growths with little or no pigment
- Discoloration of the nose
- Loss of appetite
- Crusting of the skin
Causes of Depigmentation Disorders in Cats
The causes of depigmentation in cats range from harmless genetic mutations to life-threatening diseases. The environment that a cat is exposed to, along with periods of stress or illness, can lead to progressive depigmentation of the coat. All known causes are listed below.
- Pemphigus foliaceus (an autoimmune skin disorder)
- Hereditary gene mutation (as seen in Persian, Siamese and Burmese cat breeds)
- Chediak-Higashi Syndrome
- Cutaneous lupus
- Autoimmune reactions
- Upper respiratory infections
- Periocular leukotrichia
- Waardenburg-Klein Syndrome
- Scar tissue from a wound
Diagnosis of Depigmentation Disorders in Cats
If you are concerned about visible depigmentation on your cat, or if your cat has started to produce other negative side effects in relation to the pigment change, take it in for an appointment with your veterinarian. Be sure to provide the cat's full medical history including all information about how long the depigmentation has existed and how fast it has progressed. The veterinarian will visually inspect the cat and perform a full physical examination to note all symptoms that have manifested. This will help to identify possible health issues that can cause depigmentation.
Full blood work will be needed, including a complete blood count and a biochemical profile to evaluate the cat's overall health condition. The veterinarian may listen to the heart to check if any murmur or abnormal rate exists, as this can be associated with hormonal disorders. A skin scraping from an affected area or a skin biopsy of any growths present may be collected and sent for histopathological examination. This can help determine if any cancerous tissue exists in the depigmented patches. Urinalysis can be used to see how the internal organs are functioning. The vet may decide to test for hyperthyroidism. This may be done by checking for enlarged thyroid glands in the neck, taking a serum measurement of thyroid hormone concentrations, or performing a scintigraphy.
Treatment of Depigmentation Disorders in Cats
Cats with depigmentation only require treatment if the loss of pigment has been associated with an underlying disease. Proper treatment will vary depending on the condition that has been diagnosed.
Certain disorders that cause depigmentation can be managed by a course of immunosuppressive drugs or corticosteroids. Issues such as pemphigus foliaceus can usually be managed by these prescriptions.
If a hormonal imbalance has been found in the cat, oral thyroid supplementation is generally used to treat the disorder.
If a depigmented growth has been found to be cancerous, surgical removal of the growth is the best course of action. Removing the cancer, if possible, can help stop it metastasizing to other organs in the body.
Recovery of Depigmentation Disorders in Cats
If your cat has undergone surgery, be sure to follow all at-home care guidelines as directed by your veterinarian. The incision site will need to be kept clean and monitored for signs of infection on a daily basis. Limiting stress throughout the healing process may help your cat to heal faster. Do not allow your cat to bite or chew at its stitches.
If your cat has been found to have a hormone disorder, it is likely that it will need hormone supplementation for the rest of its life. If medication has been prescribed to your cat, follow-up appointments will be needed to adjust the dosage if side effects have begun to develop. The prognosis for cats who have been diagnosed with cancer will vary greatly depending on the type of cancer that has been found and how far it has progressed. Most cases of depigmentation in cats are harmless, cosmetic occurrences that will have no affect on the happiness and length of life of the cat.