Localized Vulvodynia

Introduction

Vulvodynia is defined as a chronic discomfort or pain, consisting of burning, stinging, irritation, and rawness on the vulva. It was once believed to be a rare condition, but is now known to affect millions of women. It can be a chronic pain disorder, at times associated with other chronic comorbid pain conditions. The prevalence of vulvodynia is 8.3%. The prevalence remains stable through age 70 years and has been shown to decline thereafter. The pain can be generalized—diffuse vulvar burning or irritation—or localized—pain at a specific area, such as the vestibule or clitoris. Localized vulvodynia that was previously termed vulvar vestibulitis is currently termed vestibulodynia . The vestibule is defined as the area between the hymen and Hart's line ( Fig. 3.1 ).

History of Vulvar Pain Terminology

Vulvar pain discussion first appeared in the literature in 1861 in an article by Sims. He described a patient he saw in 1857 with vaginismus, but on further analysis of her history, she appeared to have vulvodynia. Thomas has described the condition as “excessive hypersensibility of the nerves supplying the mucous membrane of some portion of the vulva.” In 1889, Skene depicted a condition “characterized by a supersensitiveness of the vulva. … When, however, the examining finger comes in contact with the hyperaesthetic part, the patient complains of pain, which is sometimes so great as to cause her to cry out.” In the same year, Kellogg wrote about a patient with “sensitive points about the mouth of the vagina.” The topic was not readdressed until 1928, when Kelly saw a woman with “exquisitely sensitive deep red spots” that were a “fruitful source of dyspareunia.” In 1983, Friedrich reported on 13 patients with “vestibular adenitis.” Terminology has continued to change with time. The International Society for the Study of Vulvovaginal Disease (ISSVD) popularized a definition of vulvar pain in the 1980s (essential or dysesthetic vulvodynia), describing patients with a chronic discomfort and burning, stinging, irritation, and rawness of the vulva. In 1987, Friedrich proposed the term vulvar vestibulitis syndrome . There are two major forms of vulvar pain: hyperalgesia (low pain threshold) and allodynia (pain to light touch). The terminology of pain localized to the vulvar vestibule continues to undergo changes. Table 3.1 demonstrates the changes in terminology for vulvar pain that have occurred with time, up to the 2003 terminology. Concerns with the terminology were present. Recently, a new vulvodynia terminology has been approved ( Box 3.1 ).

Patients with vulvar pain localized to the vestibule have a normal-appearing vulva, other than occasional erythema ( Fig. 3.2 ). The erythema tends to be most prominent at the Bartholin's, Skene's, and vestibular duct openings. The other form of localized pain is clitorodynia. Pain associated with an abnormal vulvar appearance does not qualify for the diagnosis of localized vulvodynia ( Box 3.2 ).

Causative Theories of Vulvodynia

Many theories have been proposed for the causes of vulvodynia, including abnormalities of embryologic development, infection, inflammation, genetics, immune factors, nerve sensitization, and increased muscle tone. The exact cause of vulvodynia is unknown; there likely is no single cause.