Red, itchy and painful vulvar skin may be related to vulvar allergy, vulvovaginitis, trichomonas vaginitis and other causes. 1. Vulvar allergy: the use of vulvar cleansing drugs, unsuitable sanitary napkins and so on can cause vulvar skin allergy, which will lead to local redness of the skin, the appearance of red rashes, erythema, itching, and after scratching the rashes rupture can be painful. 2. Vulvovaginitis: the vulvar skin is stimulated by vaginal secretion, menstrual blood or local moisture, which can cause local non-specific inflammation, pain, itching, burning sensation of the vulvar skin and mucous membrane, and swelling, congestion, or erosion of the vulva can be seen in the acute stage of examination. 3. Trichomonas vaginitis: the main mode of transmission is direct transmission through sexual intercourse, the clinical manifestations of vulvar itching, increased vaginal discharge, vulvar pain, burning or pain during sexual intercourse, scratching the skin can cause vulvar redness. Vulvar skin redness, itching and pain of the causes of other aspects, it is recommended that timely medical care, clear causes, follow the doctor’s instructions for standardized treatment.