Inclusion cysts are the most common cysts of the vulva. The vulva is the area that contains the external genital organs. Inclusion cysts may also develop in the vagina. They may result from injuries, such as tears caused during delivery of a baby. When the vulva is injured, tissue from its surface (epithelial tissue) may be trapped under the surface. Some inclusion cysts develop on their own.
Epidermal cysts may develop when the ducts to sebaceous glands become blocked. Secretions from these glands then accumulate under the skin’s surface.
Both of these cysts eventually enlarge and sometimes become infected. Infected cysts may be red and tender and make sexual intercourse painful.
Cysts that do not become infected usually cause no symptoms, but they occasionally cause irritation. They are white or yellow and usually less than 1/2 inch (about 1 centimeter) in diameter.