Systemic lupus erythematosus (SLE) is a fairly rare chronic and potentially-fatal autoimmune disease. The dog’s immune system fights itself by forming antibodies that “protect” it against its own cells and tissues. This results in inflammation and tissue damage in the skin, heart, lungs, kidneys, joints, nervous system, or blood. Usually several organs are affected. SLE can be managed, but not cured. While the disease itself is chronic, signs can be acute, chronic, or both. Lifelong treatment is necessary. It is different from discoid lupus erythematosus (DLE), which is a skin disease.
The word lupus is Latin for “wolf.” (Some humans get a facial rash that has a slight similarity with a wolf’s face.)
Breeds that most typically are affected by SLE include Afghan Hounds, Beagles, German Shepherd Dogs, Irish Setters, Old English Sheepdogs, Poodles, Rough Collies, and Shetland Sheepdogs. Dogs are usually middle-aged when they get SLE. Females are not more likely than males to get SLE.
The most common significant signs of SLE are a non-erosive polyarthritis (an arthritis that affects several joints), painful muscles; shifting lameness; skin sores and blisters; proteinuria (protein in the urine); decreased platelet and white blood cell count; fluctuating fevers, and immune mediated hemolytic anemia (IMHA). Some less-significant signs are mouth ulcers, inflamed lining of the chest cavity or heart, dementia, swollen lymph nodes, and seizures. Usually, dogs with SLE are first taken to the veterinarian because of the skin problems or lameness.
Blood tests are needed for diagnosis. While all dogs won’t have the same signs, dogs with SLE typically test positive for anti-nuclear antibodies (ANA). There are so many effects of this multi-systemic disease that it’s hard to rule any one disease in or out. Diagnosis is typically made using a combination of a positive ANA test with at least two significant signs. A positive ANA test, with one significant sign plus two less-significant signs is also indicative of SLE. (SLE can be suspected if there is only one significant sign plus positive ANA, or if there are two significant signs with a negative ANA test.) It can be difficult to make a positive diagnosis since other problems, such as drug reactions and cancer, can have many of the same signs. (ANA can be positive with any chronic inflammatory disease, so if there are no other consistent pathologic or clinical signs, your veterinarian may suspect a false-positive ANA.)
Treatment is aimed at decreasing the inflammation and autoimmune activity, so treatment centers around anti-inflammatory and immunosuppressive medications such as corticosteroids (e.g. prednisone). Sometimes a second immunosuppressant, such as azathioprine, cyclophosphamide, or cyclosporine will be necessary. Specific problems, such as kidney or spleen damage, will also have to be treated. Treatment plans depend on what organs are affected.
The ultraviolet rays in sunlight can cause flare-ups of SLE, so exposure to sunlight should be limited.
Prognosis depends entirely on how each dog is affected, but owners can expect that their pets will require life-long treatment. Unfortunately, sometimes the damage caused by this disease can result in death.