There are more reasons for labia swelling and hardness, which may be caused by mycosis vaginalis, vestibulitis, vulvar cancer and other diseases. 1. Mycotic vaginitis: If mycotic vaginitis recurs, it is easy to invade and involve the labia majora tissues, resulting in localized lumps, tingling and burning symptoms. 2. Vestibular adenitis: Vestibular adenitis is a kind of inflammatory disease mainly triggered by the invasion of pathogenic bacteria into the vestibular gland, which is mainly manifested as redness, swelling, heat and pain in the vulva, as well as pus, hardness, burning and tingling in the labia majora, and so on. 3. Vulvar cancer: vulvar cancer is easy to invade and involve labia majora, urethra, rectum and other tissues, which leads to various uncomfortable symptoms of the patients, such as itching of vulva, enlargement of one or both sides of groin and pain of labia majora lump, frequent urination, urgency of urination, pain of urination, hematuria, constipation and blood in stool, etc. The swelling and hardness of labia majora can also be seen. Swollen and hard labia can also be seen in other diseases, it is recommended to go to a professional hospital to clarify the cause of the disease, under the guidance of the doctor for diagnosis and treatment.