Red, swollen, itchy and painful vulva can usually be caused by more causes, as follows: 1. Patients can observe for themselves whether there is folliculitis or boils on the skin of vulva, and folliculitis secondary to bacterial infection can cause red, swollen, hot and painful vulva; 2. Insect bites, such as mosquitoes and other insect bites; 3. Vulvar rash and eczema can also cause symptoms; 4. Vaginal secretions stimulate the vulva; 5. Vestibular gland is The vestibular gland is a normal gland at the lower end of the female vaginal opening and is susceptible to infection, resulting in vestibulitis, also known as Bartholin’s gland abscess or Bartholin’s gland cyst. It can be red, swollen, itchy, painful, and locally enlarged. The hard nodules can be small at first, such as the size of soybeans or peanuts, and continue to swell, and can be as big as quail eggs, and can even form abscesses and rupture.