Systemic lupus erythematosus (“lupus”) is an autoimmune disease with multi-system impairment that often begins with skin damage. Typical skin damage is facial erythema, discoid erythema and photosensitivity, and UV exposure can not only aggravate or reproduce skin lesions, but also cause worsening or recurrence of systemic symptoms. When summer comes, the sun is hot and the intensity of ultraviolet rays is high. If patients with lupus do not pay attention to or fail to protect themselves properly, the disease may recur. So, how can we do proper and effective protection? First, minimize outdoor activities and avoid prolonged exposure to direct sunlight. Second, when going out, you should pay attention to minimize the exposed area of the skin, such as wearing a sun hat, long-sleeved shirts and long pants, etc. Thirdly, use sunscreen correctly. If you have to go out, it is not enough to take the above sun protection measures, but you should also use effective sunscreen (SPF value between 20~30 is appropriate). This is because there are two components of pathogenic ultraviolet rays in sunlight, UV-A (wavelength 320-400nm) and UV-B (wavelength 290-320nm). Clothing can only block UV-A, but not UV-B. If lupus patients can do the above three things, they can greatly reduce the chance of recurrence and spend the summer more safely.