A Primer on Pannus in Dogs
What Is Pannus in Dogs?
The scientific name for pannus is Chronic Superficial Keratitis (CSK). It’s an autoimmune disease that affects the cornea part of the eye. Pannus is most commonly found in breeds such as German shepherds, border collies, and greyhounds but is not limited to these breeds only.
CSK occurs when the cornea is damaged by UV light rays. The dog’s immune system sends small blood vessels to the cornea in an attempt to repair the damage. Since corneas do not have blood vessels, the immune system assumes these vessels are a foreign invader and attack the corneal tissue and vessels.
The attack on corneal tissue leads to the formation of scar tissue. If this goes untreated, it will lead to severe visual impairment and, ultimately, blindness. While there’s no cure for pannus, it can be managed and treated in a way that allows your patient to continue living a full and active life.
Symptoms of Pannus
One symptom of pannus is the visual presentation of the blood vessels sent to heal the UV light damage. Reddening at the 3 o’clock and 9 o’clock hours of the pupil becomes visible when this happens. Changes in pigmentation, cloudiness, and blood vessels begin to form on the outer edges of the cornea and move inward.
Further progression of this autoimmune disease leads to discharge, thickening, and loss of pigmentation in the third eyelid of dogs. At this point, the pannus has progressed to a subclass of CSK called plasmoma.
Management and Treatment Options
Pannus can be easily confused with other eye issues in dogs, such as dry eye or corneal ulcers, so it’s important to be sure of your diagnosis before prescribing a treatment plan. If you confirm pannus in your patient, warn the owner about being especially vigilant with UV light exposure if they live at higher altitudes or are commonly exposed to such environments. If you know this is an issue for your patient, you may want to suggest to their owner a pair of UV dog goggles for when they’re outside or moving to an area of lower altitude.
When caught in its early stages, pannus is very manageable and unlikely to cause much disruption to the daily life of the pet and owner. Stopping the formation of blood vessels is key in this process. The most common treatment options are medical-grade eye drops, such as dexamethasone, prednisolone, or cyclosporine. Over time, application frequency will likely decrease if the owner continues to be cautious about UV light exposure.
However, in severe cases, sometimes surgery is necessary to remove the excess scar tissue. Otherwise, visual impairment to the point of blindness is a possibility.
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