What is Pannus and what causes it?
Pannus is an inflammatory, and potentially blinding disease of the cornea in dogs. Early in the disease, blood vessels and pigment invade the cornea, from the ear-side of the eye at first, and heads towards the nose-side of the eye. As it spreads, the inflammation can appear pink and fleshy. This is typically quite painful and irritating for the dogs afflicted with it. Eventually, the entire corneal surface can be covered, and this will render the dog blind, and can cause permanent scarring if left to develop so completely. This disease often affects both eyes, but may be asymmetrical in its presentation.
Pannus is believed to be an auto-immune condition, with a genetic basis. German Shepherds, Shepherd crosses and Greyhounds are most at risk. Ultraviolet radiation is believed to be a large predisposing factor, with the radiation altering how the immune system recognises the cornea. Once this occurs, then a large inflammatory reaction directed against the cornea occurs.
Clinical signs of Pannus
Pannus causes discomfort, and squinting with excessive tearing and eye discharge is seen. The most definitive feature of pannus is the formation of a red/pink fleshy invasion of the cornea, sometimes with white plaques. This invasion on to the cornea almost always comes from the ear-side of the eye and traverses towards the nose more with time. This disease is seen overwhelmingly most commonly in German shepherds, shepherd crosses and greyhounds. We can confirm this diagnosis by removing some cells from the inflammatory region and assessing them under a microscope. There are a few cell types that can be identified using this method that are only seen with this condition in dogs.
As pannus is an auto-immune condition, then modulating the immune system is the pinnacle of treatment. Often this involves topical “anti-rejection” drugs, such as Tacrolimus or Cyclosporine. These can either be dispensed as a drop or an ointment. Additionally, the use of topical steroids may be advised to reduce the degree of topical inflammation present. Additionally, as ultraviolet radiation has a role in this disease’s progression, using ultraviolet- blocking products can be beneficial too. We can make recommendations based on your pet’s conformation and lifestyle on what product is most appropriate. Typically, this condition improves drastically on treatment and overall the prognosis if treated is very favourable.