Vulvodynia

Basics

Description

  • Vulvar pain lasting 3 months or more; occurs in the absence of relevant visible findings, relevant lab abnormalities, or a clinically identifiable neurologic disorder
  • 2015 ISSVD (International Society for the Study of Vulvovaginal Disease) classification is based on whether vulvar pain is caused by a specific disorder or has no clear identifiable cause (1).
  • Specific disorders (differential diagnosis) include infectious, inflammatory, neoplastic, neurologic, trauma, iatrogenic, or hormonal deficiency.
  • Descriptors for unclear etiology include localized versus generalized versus mixed, provoked versus spontaneous versus mixed, primary versus secondary onset, and temporal.

Epidemiology

  • Can occur at any age, but most women diagnosed between age 20 and 40 years (2)
  • Nearly half of women opt not to seek treatment (3).
  • Patients are psychologically comparable with asymptomatic controls and have similar marital satisfaction, but poorer overall sexual satisfaction.

Incidence

  • Recent retrospective study estimates annual rate of new onset vulvodynia to be 1.8%.
  • Evidence indicates lifetime cumulative incidence approaches 15%, suggesting nearly 14 million U.S. women will experience persistent vulvar discomfort at some point in their lives (4).

Prevalence

  • Reports between 8.3% and 16%; non–clinical-based studies approximate a prevalence of 7% with validation by exam (3).
  • Studies show Hispanics are 80% more likely to present with vulvar pain compared with Caucasians and African Americans.

Etiology and Pathophysiology

  • Vulvodynia is likely neuropathically mediated:
    • Hypothesized that neurogenic inflammation sensitizes afferent nerves, and transmits impulses to the central nervous system (CNS), where reinforcing signals sustain pain loop
    • In recent investigations of vulvar biopsy specimens, increased neuronal proliferation and branching in vulvar tissue are evident when compared with tissue of asymptomatic women.
  • Pelvic floor pathology also should be considered: In one study, the vulvodynia group showed an increase in pelvic floor hypertonicity at the superficial muscle layer, less vaginal muscle strength with contraction, and decreased relaxation of pelvic floor muscles after contraction (4).
  • No cause of vulvodynia has been established. It is most likely a neuropathic pain caused by a combination of the following:
    • Recurrent vulvovaginal candidiasis or other infections
    • Immune-mediated chronic neuroinflammatory process within vulvar tissues
    • Chemical exposure (trichloroacetic acid) or physical trauma
    • Reduced estrogen receptor expression/changes in estrogen concentration
    • CNS etiology, similar to other regional pain syndromes

Genetics
Proposed genetic deficiency impairing one’s ability to stop the inflammatory response triggered by infection or chemicals; homozygosity of the two alleles of the interleukin (IL)-1 receptor antagonist occurs in 25–50% of vestibulodynia patients, compared with <10% in controls.

Risk Factors

  • Vulvovaginal infections, specifically candidiasis. Unclear if infection, treatment, or underlying hypersensitivity is the cause (3). Multiple infections compound this risk.
  • Hormonal factors: Controversial evidence proposes increased risk with use of oral contraceptive pills (OCPs); pain onset or increased severity may be associated with menopause. Symptoms may flare before menses.
  • Pelvic floor dysfunction: Increased instability of pelvic floor muscles may perpetuate vulvar tissue inflammation, leading to vascular changes and histamine release.
  • Comorbid interstitial cystitis and painful bladder syndrome; potentially related to common embryologic origin of structures
  • Abuse: increased risk of vulvodynia if childhood had physical or sexual abuse by a primary family member; causal relationship remains unclear (4).
  • Depression and anxiety (3)
  • Other neuropathic and chronic pain disorders, including regional pain syndrome

General Prevention

  • Wear 100% cotton underwear in the daytime and no underwear to sleep.
  • Avoid douching and other vulvar irritants such as perfumes, dyes, and detergents.
  • Avoid abrasive activities and tight, synthetic clothing.
  • Avoid panty liners.
  • Clean the vulva with water only and pat area dry after bathing.
  • Avoid use of hair dryers in the vulvar area.

Commonly Associated Conditions

Higher incidence of chronic pain syndromes associated with vulvodynia, including chronic cystitis, irritable bowel syndrome, fibromyalgia, migraines, depression, endometriosis, low back pain. Women with vulvodynia have a higher incidence of depression and anxiety both preceding and resulting from their symptoms (3).

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