Pruritus ani (PA) is a common local pruritus. The anus sometimes has a slight itch. If the itching is severe and does not heal for a long time, it becomes pruritus. It is a common localized neurological dysfunction skin disease. It is usually limited to the area around the anus, and some can spread to the perineum, vulva, or the back of the scrotum. It often occurs in the middle age of 20 to 40 years old and the elderly, less common in young people under 20 years old, and rarely in children. It is more common in men than in women, and people who are used to being quiet and do not exercise often suffer from this pruritus. Secondary pruritus has obvious causes and is easy to treat; spontaneous or unexplained PA is not easy to cure and often relapses, accounting for about 50% of all patients.