Redness and swelling along the labia may be caused by vaginitis, vulvitis, or allergy. 1. Vaginitis: after vaginitis, the vagina is stimulated by pathogens, such as bacteria and fungi, which may lead to an imbalance of the flora and an increase in endocrine secretion, which may occur after stimulating the labia. 2. Vulvovaginitis: clinically, vulvovaginitis may produce symptoms of redness and swelling along the labia due to increased secretion in the vulva area and stimulation of the vulvar skin by inflammatory substances. 3. Allergy: if contact with allergic substances, allergic reaction, may also lead to skin tissue stress changes, so there will be labial redness and swelling symptoms. In addition, usually need to pay attention to personal hygiene, do a good job of local cleaning, if the redness and swelling situation aggravated recommended timely medical care.