Systemic lupus erythematosus
The rate of SLE varies between countries, ethnicity, and sex, and changes over time. In the United States, one estimate of the rate of SLE is 53 per 100,000; other estimates range from 322,000 to over 1 million. In Northern Europe the rate is about 40 per 100,000 people. SLE occurs more frequently and with greater severity among those of non-European descent. That rate has been found to be as high as 159 per 100,000 among those of Afro-Caribbean descent. Childhood-onset systemic lupus erythematosus generally presents between the ages of 3 and 15 and is four times more common in girls.
Canine discoid lupus erythematosus
Discoid lupus erythematosus (DLE) is an uncommon autoimmune disease of the basal cell layer of the skin. It occurs in humans and cats, more frequently occurring in dogs. It does not progress to systemic lupus erythematosus (SLE) in dogs. SLE can also have skin symptoms, but it appears that the two are either separate diseases or DLE is a mild form of SLE. DLE in dogs differs from SLE in humans in that plasma cells predominate histologically instead of T lymphocytes. Because worsening of symptoms occurs with increased ultraviolet light exposure, sun exposure most likely plays a role in DLE, although certain breeds (see below) are predisposed. After pemphigus foliaceus, DLE is the second most common autoimmune skin disease in dogs.