The development of SLE is the result of a combination of endogenous and exogenous factors. Not only must there be a susceptible background, but external factors are important triggers, and these external factors include infections, diet, ultraviolet light, toxins, drugs, and chemical factors. Infection is the most common trigger. Not all infections cause lupus flares or exacerbations, but the majority of patients with flares are associated with infections, which may be bacterial, viral, or other infections. Ultraviolet light is also a common trigger for lupus exacerbations and flares, such as sun exposure or sunbathing. UV light damages skin epithelial cells, leading to the release of dsDNA and causing autoimmune reactions; it can induce specific immune responses by molecularly mimicking and affecting immune regulatory functions; stress can affect immune cell function by promoting neuroendocrine changes; food or drugs can affect the production of inflammatory mediators; and drugs can also regulate cellular reactivity and immunogenicity of autoantigens. Thus, the development of SLE is associated with a variety of factors.