Central Sensitization in Vulvodynia and Endometriosis: What Have We Been Overlooking So Far?

Importance: Women experience more frequent and greater pain than men, although they receive less adequate treatment and are perceived as more anxious than males. Recent clinical research has lead to hypothesize a common etiology for overlapping chronic pain conditions and mood disorders, namely, central sensitization, which originates from an alteration of pain processing pathways in the central nervous system. Objective: The aim of this review was to collect all available evidence regarding the potential role of central sensitization in vulvodynia and endometriosis. Evidence acquisition: A systematic literature search was performed between July and August 2022 using the electronic database PubMed. The extracted data were summarized using a narrative approach. Results: Ten articles were chosen for the review. Participants' mean age was 39.2 years (SD = 5.1). Among serum markers of central sensitization, nitric oxide levels were greater in women with endometriosis than in controls, whereas brain-derived neurotrophic factor and S100B levels differed among pain conditions with structural anomalies and those without. Functional magnetic resonance imaging showed different resting state networks between patients with endometriosis and controls. In neurophysiology studies, cases had reduced pain thresholds, compared with healthy controls. Lastly, self-reported questionnaires suggested a central component of pain in women with endometriosis-related dyspareunia and associated bladder/pelvic floor tenderness. Conclusions and relevance: The management of vulvodynia and endometriosis may benefit from a new perspective, which considers their possible central etiology. It is compelling that treatment of pain starts to be considered a therapeutic goal in its own right.