Vulvitis is not a disease, but refers to the inflammation of the soft folds of skin on the outside of the female genitalia, the vulva. The irritation can be caused by infection, allergic reaction, or injury. The skin of the vulva is especially susceptible to irritation due to its moistness and warmth. Vulvitis can be caused by many factors or irritants, including:

The use of colored or perfumed toilet paper
An allergic reaction to bubble bath or soap used to clean the genital area
Use of vaginal sprays or douches
Irritation by a chlorinated swimming pool or hot tub water
Allergic reaction to spermicide
Allergic reaction to sanitary napkins
Wearing synthetic underwear or nylon pantyhose without a breathable cotton crotch
Wearing a wet bathing suit for extended periods of time
Bike or horseback riding
Fungal or bacterial infections including scabies or pubic lice
Herpes
Skin conditions such as eczema or dermatitis