The causes of pubic lice on the hair include sexual contact transmission, indirect contact transmission and so on. 1. Sexual contact transmission: Sexual contact transmission is the main way of pubic lice transmission, if the infected person’s pubic hair area has pubic lice, as long as the infected person and the infected person have a one-time behavior, the process of sexual behavior, due to the fact that the pubic lice will crawl, pubic lice crawl to the other person’s pubic hair, which will cause the infection, and the chances of infection may be in 95%. 2. Indirect contact: Pubic lice may be found on the toilet lid, bed sheet and duvet cover, bath towel, underwear and pants used by the infected person, and the use of the above items used by the infected person will lead to indirect contact. If the infected person has pets, the pets may also have pubic lice on them, which may cause infection upon contact. If you find that you have pubic lice, you should go to the hospital in time, strictly follow the doctor’s instructions for appropriate treatment, and pay attention to personal hygiene in your daily life.