This is a collection of articles regarding pannus: (from professionals)

One thing I have been hearing from other breeders is that it is occurring much more frequently in the last five years or so...I had not even heard of it in my dogs before at all until this year.(one case) And remember I have been breeding the same lines the same way for about 20 years now. Like with humans chemicals and environment play a big role in disease, to much inbreeding may "weaken immune systems" but loved ones and friends I have known that have been diagnosed with Cancer , and auto-immune diseases like MS, ALS, Graves and numerous others are not inbred or had family histories so there is something in our environment, whether it is chemical or Ozone depletion or combinations of both, Dogs are increasing in auto immune diseases cancers and allergies- just like in Humans incidences of all are much more common then they used to be.

Prevention--- Seems to be those at high altitude levels and low levels near water(reflections) bright sunny days with bright snow on the ground), living in environments with greater sun exposures. It may be helpful to keep dogs out of direst sun light for long periods also keeping those heads from hangin' out the car window may be a good idea as well.. It's also a given that dogs probably don't realize looking towards the sun is bad!

related terms: chronic superficial keratitis (CSK), German shepherd pannus, Uberreiter's syndrome

Section: Overview

Pannus, also referred to as chronic superficial keratitis, is a chronic inflammation of the cornea and sometimes the third eyelid of both eyes. It arises as a gray, pink film that spreads across the eyes and eventually decreases the dog’s vision. As the lesion progresses, superficial vessels invade the cornea and the cornea becomes opaque. With time the cornea becomes thickened and the surface may become rough and pitted.

The cause of pannus is believed to be an immune-mediated inflammation of the cornea that is made worse by external factors. Exposure to ultraviolet radiation and environmental pollution increases the severity of the condition. Dogs that live in areas of extensive sunlight, especially at high elevations tend to have the worst clinical signs. Pannus is not painful, but advanced cases may lead to blindness.

Pannus occurs only in dogs. Most affected dogs are middle-aged, but the disease can develop in young adult dogs. Pannus occurs predominantly in German shepherd dogs and German shepherd-cross dogs; it also occurs uncommonly in the greyhound, rottweiler, Belgian tervuren, Border collie, golden retriever, and Australian shepherd.

What to Watch For

  Pannus usually begins as a somewhat symmetrical fleshy, pink-white film that begins at the lower, outer edges of the cornea of both eyes.
  Redness and tearing may be noted.
  With time the corneas can pigment and turn dark brown.
  White fatty deposits in the adjacent cornea may also develop.
  The entire cornea may appear opaque.
  Vision may be decreased.
  The third eyelid may appear thickened or become pink in color.
  The condition is not usually painful unless it is complicated by ulceration of the cornea.

Diagnosis

Diagnostic tests are necessary to recognize pannus and to exclude other diseases, such as the following:

  Keratoconjunctivitis sicca
  Corneal ulceration
  Corneal granulation tissue from ocular trauma
  Pigmentary keratitis
  Squamous cell carcinoma of the cornea and/or third eyelid

The diagnosis of pannus is almost always made based upon the clinical history and the appearance of the eye. Your veterinarian will usually perform a complete eye exam that includes:

  Schirmer tear test to rule out tear deficiency (dry eye)
  Fluorescein staining to look for ulceration of the cornea
  Thorough examination of the eyelids and adjacent structures of the eye

Your veterinarian may elect to refer your dog to a veterinary ophthalmologist for a comprehensive eye examination, to confirm the diagnosis and to obtain advice on the best therapies to institute.

 

What is pannus?

Pannus, or chronic superficial keratitis, is a condition of ongoing inflammation of the cornea (the surface of the eye). Pannus begins as a grayish haze. Gradually blood vessels and pigmented cells move into the normally transparent cornea. As the inflammatory changes spread across the cornea, vision is affected. The condition gradually worsens and usually affects both eyes.

In atypical pannus, the third eyelid is affected rather than the cornea. This is most common in German shepherds.

Pannus appears to be caused by an inappropriate response of the immune system. It occurs more frequently and is harder to control in dogs that live at high altitudes and/or are exposed to increased levels of ultraviolet radiation.

 

The mode of inheritance is unknown.

What breeds are affected by pannus?

This condition is seen most often in purebred and crossbred German shepherds and in the Belgian Tervuren.  It also occurs in the Belgian sheepdog, border collie, dachshund, greyhound and Siberian husky

This is a disorder primarily of middle-aged dogs (4 to 7 years) and there is an increased incidence in dogs that live at high altitudes and/or are exposed to increased levels of ultraviolet radiation.

For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

What does pannus mean to your dog & you?

If untreated, the blood vessels and inflammatory cells will spread over your dog's normally transparent cornea, gradually darkening and scarring it, and causing visual impairment. This can occur slowly over months or years, or it can occur rapidly to involve the whole cornea within a few months. The condition does not appear to be painful.

Lifelong treatment is required to control this disorder (see below). Usually pannus can be well-controlled, although it is harder to control in dogs living at high altitudes (above 1500 metres). Sometimes lesions will worsen in periods of environmental irritation or increased ultraviolet exposure, or if medication is given irregularly.

How is pannus diagnosed?

Diagnosis is made based on the signalment (breed and history) and the typical changes in your dog's cornea.

FOR THE VETERINARIAN: You will see bilateral lesions consisting of vascularization, pigmentation, or a combination - usually starting in the temporal or inferiotemporal quadrant and progressing centrally.  Atypical pannus may affect the nictitating membrane without affecting the cornea. The leading edge of the nictitans is depigmented and the palpebral surface is red and thickened. Treatment is similar to that for typical CSK.

How is pannus treated?

Usually pannus can be well-controlled. However treatment must be lifelong and consistent, or the lesions will return and worsen.

The goal of treatment is to prevent vision loss, or to return as much vision as possible if there is loss. This is done with the use of anti-inflammatory drops in the eye. Drugs used alone or in combination include corticosteroids and cyclosporin A. Your veterinarian will make specific treatment recommendations based on the severity of the changes to your dog's eyes, and the response to therapy. Usually therapy begins with 4 treatments a day. As the size of the area affected decreases, treatments will be decreased to the lowest frequency that controls the condition.

Once effective treatment is established, your veterinarian will evaluate any changes once or twice a year, or if you notice a worsening of the condition as may occur in periods of environmental irritation or increased ultraviolet exposure.

Breeding advice

Affected dogs should not be used for breeding. Breeding of close relatives should be avoided as well.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Where to find more information?

Roberts, S.M. 1995. Pannus. In J.D. Bonagura and R.W. Kirk (eds.). Kirk's Current Veterinary Therapy XII Small Animal Practice. p. 1245-1248. W.B. Saunders Co., Toronto.  - This has good information on treatment, including for advanced or refractory lesions.

Copyright © 1998 Canine Inherited Disorders Database. All rights reserved.
Revised: April 11, 2000.

Chronic Superficial Keratitis, in Dogs
(Pannus)

Pannus is an immune mediated corneal disease primarily found in the German Shepard breed although other predisposed breeds include Greyhounds, Huskies, and Dachshunds. Ultraviolet light and altitude influence the severity of the disease. Pannus is a progressive, non painful, inflammatory disease of the cornea, conjunctiva, and sometimes the third eyelids (when affecting the third eyelid, it is termed "atypical pannus" or "plasmoma"). Other breeds reported to have problems with pannus include Poodles, Border Collies, and Labrador Retrievers. Variable proportions of pigmentation, corneal vascularization, granulation tissue, and cholesterol deposits characterize Pannus. The corneal changes usually begin on the lower outside surface of the eye. Both eyes are affected, though the diseased regions may be asymmetric. Some dogs also have dry eye problems. As the disease progresses, blindness can develop. The cause of Pannus is not well understood, but several factors are involved: The breed incidence suggests a heritable predisposition. Additionally, UV (ultraviolet) radiation plays an important role as an inciting and propagating factor. Dogs living at high altitudes and low altitudes (water reflected) are more severely affected. Also, auto immunity and possibly genetics play a part.

Another contributing factor is exposure to sunlight or ultraviolet radiation. Animals living at higher elevations or near water have additional UV exposure and, in such situations, the pannus condition may become worse. The influence of elevation is minimal in the San Francisco Bay Area; however, limiting sunlight exposure may help slow progression of the disease. Some people have had some success in getting their dogs to wear protective visors or goggles.

 

CHRONIC SUPERFICIAL KERATITIS (PANNUS)

Chronic Superficial Keratitis (Pannus) is a disease seen most commonly in the German Shepherd, but does occur in other breeds. A progressive change occurs where blood vessels and scar tissue invade the cornea. This change usually begins in the temporal (outer) or ventral (lower) quadrant of the cornea, and severe cases can involve most or all of the corneal surface area resulting in blindness. With chronicity the affected areas become black with pigmentation.

It is believed that Pannus is an immune mediated disease. That is, some subcellular change has occurred in the cornea which the immune system then recognizes as abnormal resulting in an immune mediated attack in the cornea almost as if the cornea was foreign or transplanted tissue. It is suspected that the German Shepherd has a genetic predisposition to this disease, but the damage to the cornea which starts everything is thought to be associated with ultraviolet radiation. The first reports of cases of Pannus came from Austria and in the United States - from Colorado, both areas of higher elevation. Today, Pannus is diagnosed world wide, however it is well recognized that cases of pannus are more severe and harder to treat in areas of higher elevation, supporting the UV radiation theory. It is hypothesized that dissipation of the ozone layer has resulted in greater exposure to ultraviolet radiation.

makes sense then to treat Pannus with medications that locally suppress the immune reaction. Steroids (such as dexamethasone and prednisolone) are anti-inflammatory medications which provide some immunosupression as a side effect. Cyclosporine, is a drug which has immunosupression as it's primary mode of action, and applied topically alone or in combination with steroids often results in better control of Pannus than the use of steroid alone.

Cyclosporine has been used by veterinary ophthalmologists in the treatment of pannus for 12 years now. A 1% or 2% solution is most often used, and was prepared in an oil base - usually olive, corn or vegetable oil. About five years ago a 0.2% cyclosporine ophthalmic ointment called Optimmune (Schering Plough) became available to all veterinary practitioners for the treatment of another eye disorder - keratoconjunctivitis sicca or dry eye - where it is quite effective. In pannus cases, however, I find the 0.2% ointment produces less success than the 1% solution. With treatment, the active vascularization and granulation tissue often resolves, but the scarring and pigmentation may improve somewhat slowly or not at all.

Recently, Sandoz has modified the formulation of the cyclosporine from which we make up the 1% or 2% solution. The newer formulation is called Cyclosporine Neoral, and it is a microemulsion. A microemulsion can be diluted into other solutions rather than oils. This is advantageous as the oil base of these mixtures would sometimes cause skin irritation around the eye, and could result in oil stains on the furniture if the dog rubbed its face on the sofa for example. The Cyclosporine Neoral microemulsion can be diluted into a bottle of dexamethasone or prednisolone eyedrops, simplifying the treatment regime. Initially some dogs find the newer formulation more irritating, but after a few weeks of treatment it is tolerated well. There are legal considerations to the use of unlicenced pharmaceuticals when a licenced product (Optimmune) is available on the market. If the use of cyclosporine is indicated, cases should be treated with Optimmune initially, and the use of unlicenced mixtures should be considered only if lack of response to treatment is noted on subsequent examinations.

A related condition where a similar immune mediated reaction is confined to the conjunctiva and the third eyelid is called PLASMOMA or Plasmacytic Lymphocytic Conjunctivitis of the third eyelid. This variation is also much more common in the German Shepherd. Compared to Pannus, plasmoma is less threatening to the vision, may cause more discomfort, and is somewhat more resistant to the treatment regime which is the same as for Pannus.

Reduction of exposure to ultraviolet radiation is also helpful in the longterm control of Pannus. Keeping the dog indoor during the sunniest part of the day; providing a doghouse shelter; or trying a specialty pair of canine sunglass goggles called Doggles may prove very helpful.

Since Pannus is an immune mediated disease, it is managed by treatment but not cured. Ongoing treatment for life is needed to maintain vision.

Pannus

Chronic superficial keratitis or pannus is an eye condition in which there is inflammation of the cornea with no apparent cause. Pannus is primarily a condition of German Shepherds but is also seen in Border collies, Belgian Tervurens, greyhounds, and mixes of these breeds. With pannus, the cornea of affected dogs becomes infiltrated by white blood cells, scar tissue, blood vessels and pigment. The result is a discoloration to the cornea that clouds full visualization of the iris and the rest of the inside of the eye. There is no known specific cause for the disease but in the German Shepherd it is believed to be either autoimmune or related to irritants like dust, pollen, altitude and sunlight.

Pannus is bilateral, or affects both eyes, and is usually first noticed in dogs between 3 and 5 years of age. The eye lesions are often pinkish white scar-type tissue that begins at the lower outer corner of the eye and spreads across to the center of the eye. In dogs with very severe pannus, the loss of the normally clear cornea worsens until the animal becomes blind. It is important to note that the condition is not usually associated with pain or corneal ulceration.

Diagnosis is based on the characteristic eye lesions in a typical breed in the absence of any other eye abnormality that could cause corneal damage like inadequate tear production or eyelid abnormalities.

Pannus is a condition that can be controlled but not cured. For this reason, owners must be aware that treatment is lifelong. Initially, affected dogs are treated with an injection of steroid into the tissues around the eye and then continued at home with topical steroid ointment or drops. Topical steroid treatment prevents continued vessel and scar formation in the cornea but will not reverse pigmentation. Long term topical treatment is essential. If owners stop or forget to treat for even a short period of time, the patient will relapse. In severe cases of pannus, surgery can be performed to remove the top layers of the cornea and remove the lesions. Treatment must be continued even after surgery, however, or scarring and pigmentation will return.