Vestibulodynia is a general term used to describe pain in the vestibule. The vestibule is the tissue within the vulva that sits at the opening of the vagina. The vestibule is the transition between external and internal, just like a vestibule of a building is the entrance.
Vestibulodynia can be considered a subcategory of vulvodynia. Vulvodynia is an even broader term used to describe chronic pain in the vulva. The terms vulvodynia and vestibulodynia are really only a description of symptoms, though they are often given as a diagnosis. Vulvodynia is typically used to describe generalized pain in the vulva, where the patient has chronic vulvar pain in external regions of the vulva rather than just in the vestibule. Ongoing research has improved our understanding of the underlying biological causes of pain, so terminology has changed and gotten more specific. ISSWSH, alongside two other international societies, published updated terminology in 2015.(1) We now recognize a few subtypes of vestibulodynia based on the root cause of the pain:
- Neuroproliferative vestibulodynia
- Hormonally-mediated vestibulodynia
- Inflammatory vestibulodynia
The vestibule tissue is fundamentally different from the skin around it, and even develops from a different part of the embryo. This inherent biological difference is crucial to understanding what causes pain specifically in the vestibule. In people with hormonally-mediated vestibulodynia, the vestibule tissue is painful because it is not getting the hormone signals that it needs. Hormones are molecules that our cells use to communicate, and these messages are important for any cell to be healthy. The vestibule tissue is very sensitive to a lack of hormone signals. Anything that causes the estrogen or testosterone levels in the body to drop (or change) can cause the vestibule tissue to become irritated and painful. Often the cause is medications that lower hormone levels in the body or the levels decreasing due to menopause or breastfeeding. The reasons that some people develop vestibulodynia and others do not is still being investigated (see below).