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Is it Systemic lupus erythematosus? Or Discoid lupus? German shepherds are prone to discoid lupus, which looks like SLE but is usually confined to the face, especially the area around the nose. Dogs with discoid lupus usually get phemphigus, which is another immune mediated disease.
The disease normally starts as loss of pigment around the nose. There may be scabby sores or just scaling of the nasal tissue. The surface of the nose may change from its typical cobblestoned appearance to a smooth surface. As this disease progresses it can cause deep sores on the borders of the nose where it meets normal skin and the sores start to progress up the bridge of the nose. Some dogs seem to be really bothered by this condition and others show little reaction to the sores.
Ultraviolet light seems to make the sores worse, so the disease may appear to be seasonal. It is more common in areas in which exposure to ultraviolet light is increased, such as high altitudes. If the depigmentation leads to sunburn, squamous cell carcinoma becomes more likely than in other dogs. Topical sunscreens can be very beneficial, although it is hard to get dogs to leave them on. Keeping the dog in during the peak sunlight hours is probably the most effective way to prevent excessive exposure to UV light.
Treatment depends on the severity of the disease. In many cases, topical treatment will be all that is necessary, using a corticosteroid ointment (Panalog, Synalar and others). It is usually necessary to use a fairly potent corticosteroid. Vitamin E supplementation is sometimes beneficial but can take several months to show much effect. Severe cases require treatment with corticosteroids. It is possible that other immunosuppressive therapy such as gold salts or azathioprine (Immuran) could be beneficial but this is rarely necessary to consider. In people, this condition is often responsive to antimalarial medications but I do not know if this is safe or effective therapy for dogs.
Systemic Lupus Erythematosus
This is a rare disease of the immune system. In this disease, the immune system forms antibodies against the nuclear component of its own cells. This can cause a variety of effects but the most common ones are arthritis, kidney disease, skin disease and blood disorders (anemia and/or decreased in platelet numbers). A great number of other effects and side effects of this disease can occur so it is hard to rule in or rule out when faced with a multi-systemic disease. In general, this disease is not considered to be present unless testing to determine if antibodies against the nuclear elements of the cells are present AND clinical signs of at least two of the common disorders are present. Even then, it is hard to be sure that this disease is actually the problem. Some drug reactions and cancers can produce almost identical clinical signs and many problems produce some of the clinical signs. Treatment usually involves the use of immunosuppressive medications, most commonly corticosteroids such as prednisone. Often, a second immunosuppressive agent must also be used. Azathioprine, cyclophosphamide and cyclosporine are examples of these medications. Lupus is not curable but it is often possible for a dog to live with it successfully. Some of the disorders that resemble lupus are curable, especially if a cause can be identified. Continuous monitoring of patients suspected of having lupus should be part of the treatment, due to the possibility of another problem, the multitude of side effects that can occur and the potential for problems from the medications used to treat it.
Hope this helps.