Idiopathic vulvodynia. Clinical evaluation of the pain threshold with acetic acid solutions.
Idiopathic vulvodynia is vulvar discomfort in which a diagnosis has not yet been established. As in other idiopathic pain syndromes, the involvement of primary afferent fibers (PAFs) has been postulated as playing a role in the pathogenesis and maintenance of idiopathic vulvodynia. Capsaicin induces the release of substance P (SP) by PAFs, producing vasodilation and increasing vascular permeability (neurogenic inflammation). Likewise, it has been shown that acid solutions can stimulate PAFs with the release of SP. To evaluate the pain threshold in women with idiopathic vulvodynia, 10 patients with vulvar pain but without significant vulvar physical changes and 10 asymptomatic controls received topically applied acetic acid solutions with increasing hydrogenionic concentrations (pH 3, 2.5, 2, 1.5, 1.2). Results related to pain threshold and pain time monitoring and intensity were analyzed with Fisher's exact and Wilcoxon's tests, respectively. Our data suggest that in idiopathic vulvodynia the pain threshold for acid solutions is decreased, probably in relation to increased sensitivity of PAFs involved in the transduction of painful signals.
Sonni
L
L
Institute of Gynecology, University of Florence, Italy.
Cattaneo
A
A
De Marco
A
A
De Magnis
A
A
Carli
P
P
Marabini
S
S
D000085:Acetates / Q000494:pharmacology; D019342:Acetic Acid; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology*; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D014845:Vulvar Diseases / Q000503:physiopathology*
D000085:Acetates; D019342:Acetic Acid