Injury to the vulva caused by rough movements during sexual intercourse.
Allergy of the labia or skin around the labia to items such as condoms and lubricants used during sexual intercourse, resulting in atopic eczema and contact dermatitis of the vulva, etc.
Lack of hygiene during sexual intercourse or the presence of pathogenic infections in the external genitalia of sexual partners, resulting in pathogens invading the vulva or vagina and causing vulvovaginitis or vaginitis.