The common causes of acne underneath a woman include vulvar folliculitis, condyloma acuminatum, pseudo warts and so on. 1. Vulvar folliculitis: vulvar folliculitis is mainly caused by non-specific purulent bacteria invading the vulvar hair follicles due to inflammatory diseases, in which scratching, friction, high temperature, humidity and so on are its triggers. It is characterized by redness, swelling and pain of the skin around the mouth of the hair follicle, and the gradual formation of conical papules and pustules. 2. Condyloma acuminatum: this disease is caused by human papillomavirus infection, in which high-risk sexual behavior, immunity decline is a high-risk factor, manifested in the vulva with small light red papules, papillomavirus, corns or cauliflower pattern warts, moist and soft and other symptoms. 3. Pseudo-warts: the cause of this disease is unknown, may be associated with vaginal candida, trichomonas infection and other factors, manifested in the inner lips of the labia minora and the vestibule of the vagina on the gray or reddish pimples, occasional itching and other symptoms. It is recommended that patients go to regular hospitals in a timely manner, under the guidance of a professional physician to clarify the cause of the disease, and actively treat it to avoid delaying the condition.