Systemic Lupus Erythematosus in Domestic Animals

The study of spontaneously arising diseases of domestic animals is of great value in understanding the pathogenesis of equivalent disorders of humans. Multisystemic autoimmune disease is recognized less commonly in the dog with the most frequent co-presentation being of autoimmune hemolytic anemia and thrombocytopenia (Evans syndrome). Systemic lupus erythematosus (SLE), when defined by strict criteria, is in fact a relatively rare disorder. Autoimmune disease appears far less common in the two other major companion animal species, the cat and horse. One well-recognized SLE-overlap syndrome occurs in German shepherd dogs with pyrexia, lethargy, wasting, polyarthritis, and high-titered serum antinuclear antibody (ANA). It is also of note that many dogs presenting with vague clinical illness termed pyrexia of unknown origin are ANA positive and proposed to have some form of immune mediated disease. Spontaneously arising SLE in the cat is at best a rare occurrence. However, in addition to the spontaneous disease, cats are known to develop drug-induced lupus. This species suffers relatively commonly from hyperthyroidism, generally related to the presence of a functional thyroid adenoma. Finally, as far as horses are concerned, SLE is rarely reported in them. The reported clinical signs include cutaneous lesions (distal limb edema, panniculitis, mucocutaneous ulceration, focal alopecia, scaling and leukoderma), polyarthritis, anemia, purpura, lymphadenopathy, fever, anorexia, and weight loss.