Systemic lupus erythematosus mainly has four major causes: The first is related to the environment. Long-term exposure to sunlight, or living in a humid environment, may trigger the onset of systemic lupus erythematosus. Secondly, there is a certain genetic predisposition to systemic lupus erythematosus. If the parents have systemic lupus erythematosus, the probability of their offspring developing the disease is higher. Thirdly, systemic lupus erythematosus is also related to estrogen, which is why, clinically, lupus is more commonly seen in women of childbearing age and less often in men. Systemic lupus erythematosus is also associated with some specific infections, such as bacterial or viral infections, which may trigger a lupus flare-up.