Streaks on the buttocks, if they are purplish red or silvery white, are considered to be more likely to be expansion lines. Swelling streaks are caused by excessive localized skin growth, such as rapid weight gain or overgrowth, which can cause the elastic fibers of the skin to break down and thus form. In the early stages, they can appear as raised purplish streaks and may sometimes be itchy. For older swelling lines, they may appear as silvery-white, depressed streaks. Swellings have no effect on health, but can affect aesthetics. It is recommended to control the weight to avoid excessive growth and to pay attention to the early swelling lines can try topical topical vitamin A cream or go to the regular hospital dermatology department and consult cosmetic laser treatment, while for the swelling lines that become silvery-white, there is generally no effective treatment method.