Vogt-Koyanagi-Harada Syndrome in Dogs

Vogt-Koyanagi-Harada syndrome was researched and discovered by the scientists Vogt, Koyanagi and Harada. VKH disease is also referred to as Uveodermatological syndrome (UDS). The body’s overactive immune system sends T-cells to attack the melanocytes.  T-cells are a type of white blood cell which work with the body’s immune system to search and destroy “invaders” in the body.  The “invaders” are usually infected cells that have turned into viruses, not melanocytes. T-cells mature in the thymus and are also known as T-lymphocytes.

80% of the cases with Vogt-Koyanagi-Harada syndrome occur in the Akita breed.  It is also more frequently found in male dogs.  Symptoms may appear in puppies as young as 6 months of age or in older dogs.

Clinical signs of the disease sometimes appear after a sudden stressful period. The T-cells usually start attacking the eyes of the dog, and then affects the pigmentation of the skin and coat. Unlike humans with VKH, dogs do not experience meningitis or deafness.  The disease is usually not life-threatening but left untreated, can cause pain and eventually blindness.  If your dog is showing signs of VKH disease he should be seen by a veterinarian.

Vogt-Koyanagi-Harada syndrome (VKH disease) is an autoimmune disease that affects people of Asian, Hispanic, Middle Eastern and Native American descent. VKH disease attacks the melanocytes in the body. Melanocytes are the skin cells that produce the pigment melanin. Melanin is the substance that gives pigment (color) to our skin, hair and eyes. Vogt-Koyanagi-Harada-like symptoms can occur in certain dog breeds such as the Akita, Samoyed, Siberian Husky, Old English Sheepdog and the Australian Shepherd.

Symptoms may include:

• Inflammation of the eyes
• Bloodshot eyes
• Excessive tearing
• Squinting 
• Sensitivity to light
• Whitening of the coat, skin, nose, lips, nails, footpads and scrotum
• A black dog slowly turns solid white.

Secondary glaucoma, cataracts or retinal detachment may cause the following symptoms:

• Pain
• Bulging eyes 
• Partial blindness
• Cloudy cornea
• Blindness

• Vogt- Koyanagi-Harada Syndrome in dogs is believed to be an auto-immune disease; this means that the body’s immune system attacks its own cells
• Genetic - inherited
• Some researchers believe that the disease is triggered by a viral infection

In addition to a physical exam where the veterinarian may check your dog’s temperature, pulse and blood pressure,  he will perform an ocular exam, which may include a pupillary light reflex test. Further investigation may include a Schirmer tear test, measurement of the intraocular pressure, and a checking of the interior of the eye.  The doctor will also recommend taking a complete blood count and a serum chemistry panel.

If the veterinarian suspects Vogt-Koyanagi-Harada syndrome he may also want to take a skin biopsy test. Skin biopsies take only a small sample of skin. The results of a skin biopsy from patients with Vogt-Koyanagi-Harada usually shows acanthosis of the epidermis (thickening of the cell layer of skin) and melanin is decreased or absent in the sample.

Once VKH is diagnosed, the veterinarian will want to start your dog on immunosuppression therapy which may include systemic and topical anti-inflammatory medications. The dosage of the medications will vary with each canine depending on the severity of the symptoms.  Most veterinarians will start the patient on higher doses of medications and then taper off once the disease is in remission.

Your dog might be prescribed prednisone and then azathioprine (once in remission). Immunosuppression drugs may have side effects such as increased thirst, hunger, susceptibility to bacterial infections, loss of energy, vomiting and panting. Steroid eye drops or injections of steroids may be administered into the patient’s conjunctival membrane.

Although there is no known cure for Vogt-Koyanagi-Harada syndrome in dogs, the disease can be kept under control with long-term immunosuppressive medication.  It is important to follow the veterinarian’s treatment plan.  The patient must have regular follow-up visits to monitor his progress and to evaluate if there are any side effects to the medications. Regular ocular exams and tests must be performed to help assess any further damage to your dog’s eyes. Dogs that have partial eyesight loss or blindness can still live full and happy lives with your patience and assistance.