For most people, Lupus in a mild disease affecting only a few organs, but for others, it can be serious, or even life threatening. Lupus is often called a woman's disease despite the fact that men can be affected as well. Lupus can occur at any age, although it occurs most often in women who are in their 30's and 40's. Factors which activate autoimmune disturbances that cause lupus are not known. Genetics, viruses, ultraviolet light, and drugs may all play some role.
Genetic factors increase the tendency of developing autoimmune diseases.
Autoimmune diseases such as lupus, rheumatoid arthritis, and thyroid disorders are more common among relatives of patients with lupus than the general population. Some scientists postulate that the immune system in lupus patients is more easily activated by external factors like viruses or ultraviolet light. Sometimes, symptoms of lupus can be precipitated or aggravated by only a brief period of sun exposure. It is also known that women patients with systemic lupus not infrequently experience worsening of symptoms prior to their menstrual periods. This phenomenon, together with the female predominance of those with the disease, suggest that female hormones play an integral role in the expression of systemic lupus.