What is Uveitis in Dogs?

Introduction

During a lazy Sunday afternoon, Emily was snuggling with her cherished Greyhound, Luna, when she noticed that Luna’s eye appeared red and swollen. Alarmed by this unexpected development, Emily quickly recognized that her beloved pet needed professional care and took her to the veterinarian. After a detailed examination, the vet diagnosed Luna with uveitis, an inflammatory eye condition that can affect dogs.

Uveitis is inflammation of the uvea (the iris, ciliary body, choroid, and retina). The most common cause of uveitis in dogs is a bacterial infection, and bacterial infections may be systemic or localized. Systemic diseases occur when bacteria enter the bloodstream and spread throughout the body, and localized infections usually involve only one area of the body.

Canine uveitis occurs in dogs of any age, breed, or sex. However, certain species appear to be predisposed to developing this condition. These include Boxers, Golden Retrievers, Labrador Retrievers, Poodles, Rottweilers, Shetland Sheepdogs, Yorkshire Terriers, and Dobermanns.

Causes of Uveitis in Dogs

There are several types of uveitis. Some are infectious; others are non-infectious. Bacteria, viruses, fungal infections, parasites, or protozoa typically cause contagious uveitis. Non-infectious uveitis is usually due to an autoimmuneresponse, hormonal imbalance, or genetic mutation.

Most cases of canine uveitis are idiopathic, meaning no known potential cause has been identified. However, certain breeds are predisposed to developing uveitis. Boxers, Doberman Pinschers, Golden Retrievers, German Shepherds, Labrador Retrievers, Rottweilers, Shar Peis, Siberian Huskies, and Yorkshire Terriers.

Canine uveitis is classified according to its location within the eye. The anterior uvea refers to the front half of the eye, whereas the posterior uvea covers the back half.

Forms of Uveitis in Dogs

Posterior Uveitis

Posterior uveitis is the most common type of uveitis in dogs.

Common causes of posterior uveitis include

• Leukemia
• Mast Cell Tumors
• Systemic Inflammatory Diseases
• Diabetes Mellitus
• Thyroid Disease
• Lupus
• Sarcoidosis
• Lyme Disease
• Feline Immunodeficiency Virus (FIV)
• Canine Herpesvirus 1 (CHV-1)
• Ehrlichia Canis
• Bartonella henselae

Posterior uveitisis most frequently seen in older dogs. Other factors that contribute to the development of posterior uveitis in dogs include:

• Genetic predisposition
• Exposure to toxins
• Trauma
• Surgery
• Radiation Therapy
• Ophthalmic procedures

Anterior Uveitis

Anterior uvea is rarer than posterior uveitis. Most cases of canine anterior uveitis are secondary to bacterial infections. Bacterial infections of the eye are most commonly caused by:

• Staphylococcus Aureus
• Streptococcus Viridans
• Pseudomonas Aeruginosa
• Escherichia Coli
• Proteus Vulgaris
• Klebsiella Pneumoniae
• Serratia Marcescens
• Enterobacter Cloacae
• Haemophilus influenzae
• Actinomycetes

Uveitis can also be triggered by exposure to toxins. Certain chemicals can trigger an allergic reaction in the eye. Examples of these toxins include:

• Perfluoroalkyl Acids (PFASs)
• Parabens
• Phthalates
• Triclosan
• Sodium Dodecyl Sulfate (SDS)
• Benzophenones
• Ethylene Glycol Monomethyl Ether (EGME)

Infectious uveitis is more likely to occur in young animals. It is often associated with trauma or surgery.

Non-infectious uveitis can be divided into two categories:

• Autoimmune Uveitis

This type of uveitis occurs when the immune system attacks healthy tissue in the eye. The most common forms of autoimmune uveitis involve the retina.

Retinal autoimmunity is characterized by inflammation of the retina. TAs a result, the retinal cells may become damaged, leading to vision loss.

• Hormonal Uveitis

Hormonal uveitis is a disease that affects the eye’s immune system. It is caused when the body produces too much estrogen, which causes inflammation in the eyes. In some cases, hormonal uveitis can cause blindness if left untreated.

Symptoms of Anterior Uveitis in Dogs

Symptoms vary depending on the type of uveitis. Some dogs may not show any signs at all. Others may be lethargic, listless, and reluctant to move. They may appear blind because the pupil is dilated. In addition, their eyes may be red, swollen, painful, or discharge pus.

Some dogs with uveitis may have difficulty breathing, wheezing, coughing, or experiencing shortness of breath. Their saliva and urine may also be abundant because of the inflammation in their kidneys (pulmonary hypertension).

Other dogs with uveitis may appear listless and depressed. They may rub their eyes constantly, and their pupils may dilate excessively. They may have trouble focusing, and they may seem confused.

Other common signs of uveitis include:

• Painful, swollen eyelids
• Discharge from the eye
• Sensitivity to bright light
• Difficulty focusing
• Loss of appetite

Diagnosis of Uveitis in Dogs

Idiopathic uveitis is the most common diagnosis of uveitis from a nonocular cause (40% to 60% of cases).3-5. Therefore, the first step in diagnosing uveitis is determining whether the problem is acute or chronic.

Acute uveitis is a sudden onset of symptoms lasting up to three days. Chronic uveitis is a gradual worsening of symptoms over at least six weeks. Once it’s determined that the problem is either acute or chronic, the next step is identifying the specific type of uveitis.

To do so, the vet performs a thorough ophthalmic exam. Depending on the exam results, additional diagnostic tests may be required. It is essential to check for some infections to see if there is any underlying cause for the inflammation, but unfortunately, the reason is usually never found.

Uveitis can be diagnosed using a combination of clinical examination, laboratory testing, and imaging studies.

• Clinical Examination: A complete ophthalmologic exam is performed to determine whether there is any evidence of uveitis. During the exam, the vet checks the pupil size, color, shape, and symmetry of the eyes. In addition, they examine each eye’s cornea, conjunctiva, lens, and fundus. 
• Laboratory Testing: Blood samples are collected to test for various antibodies. Antibodies are proteins produced by the immune system in response to foreign substances.
• Imaging Studies: Imaging studies detect abnormalities in the eye. Ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and radiographs are examples of imaging techniques used to examine the eye.
• Ophthalmic examination: This is the process of examining the eyes. It includes using instruments such as slit lamps, fundus cameras, tonometers, etc. The study helps us determine if there is any damage to the eye’s lens, retina, optic nerve, cornea, or other structures. This examination is performed to diagnose diseases like glaucoma, cataracts, macular degeneration, diabetic retinopathy, etc.

Treatment of Uveitis in Dogs

Treating uveitis requires a multidisciplinary approach involving veterinary medicine, nutrition, and environmental modifications. Veterinarians treat uveitis by administering anti-inflammatory drugs, antibiotics, steroids, and immunosuppressants.

1. Anti-Inflammatory Drugs: Anti-inflammatories reduce the production of cytokines, which are chemical messengers released by white blood cells. Cytokines cause inflammation. The goal of treating uveitis with anti-inflammatories is to reduce the inflammation in the eye.
2. Antibiotics: oral medication antibiotics are prescribed when bacteria are detected in the eye. They help prevent further infection.
3. Steroids: Steroid medications are given to control swelling and pain. They decrease the number of inflammatory cells in the body.
4. Immunosuppressant Medications: Immunosuppressant medications slow down the immune system. This allows the body to heal itself without causing damage.
5. Nutrition: Nutritionists recommend feeding dogs diets high in antioxidants such as vitamins C and E. These nutrients protect against free radical damage caused by releasing reactive oxygen species during inflammation.
6. Environmental Modifications: Environmental modifications include keeping the dog indoors, limiting exposure to sunlight, and providing shade from direct sunlight.

Prevention of Canine Uveitis

• To prevent uveitis, vaccinate your dog against distemper, parvovirus, adenovirus, rabies, and coronavirus. Vaccines should be given every six weeks until 12 months of age.
• In addition, avoid giving your dog flea products containing pyrethrins. Fleas can transmit bacteria that cause infectious canine hepatitis.

• Avoid exposure to cats and rabbits. Cats and rabbits can transfer feline herpesvirus one and rabbit calicivirus to dogs.
• Exercise your dog frequently. Exercise helps maintain muscle tone and improves circulation.
• Keep your dog away from water sources. Water can irritate the eyes.
• Do not allow your dog to swim. Swimming pools contain chlorine, which can burn the eyes. Use caution when handling your dog. Be careful not to poke your fingers into their eyes. Be sure to wash your hands after touching your dog.
• Take care of any cuts or wounds on your dog’s face. Wounds can become infected.
• Make sure your dog has plenty of fresh air. Exposure to smoke and fumes can worsen symptoms of uveitis. Call your veterinarian immediately if you notice any changes in your dog’s behavior. Changes in behavior may indicate that your dog has developed uveitis.

Frequently Asked Questions