Etiology and diagnosis of coital pain.

Coital pain is the leading symptom of two major sexual disorders, dyspareunia and vaginismus. According to the new International Classification on Female Sexual Disorders they are included under the category of "Sexual Pain Disorders". Dyspareunia has long been considered to be psychogenic. On the contrary, it has solid biological bases: location of pain and its characteristics are the strongest predictors of its organicity. Biological factors include hormonal, inflammatory, muscular, iatrogenic, neurologic, vascular, connective and immunitary causes. A specific pathology of pain is in play when the meaning of pain shifts from the "nociceptive" domain, when it signals an ongoing tissue damage, to the "neuropathic" dimension, when pain is generated within the pain system itself, with increased peripheral input and/or lowered central pain threshold, as happens in chronic vulvar vestibulitis. Vaginismus, with its associated defensive contraction of perivaginal muscles when intercourse is attempted, is credited to be the pelvic expression of a more general muscular defense posture, associated with a variable phobic attitude towards coital intimacy. Vaginismus may prevent intercourse in the most severe degrees, whilst in the milder ones it becomes a cause of dyspareunia. Psychosexual factors--loss of libido and arousal disorders, associated with, or secondary to, sexual pain related disorders--may contribute to the worsening of coital pain over time, alone or when associated to couple problems. The clinical approach should aim at diagnosing biological, psychosexual and context-dependent etiologies. The psychobiology of the experience of sexual pain needs to be addressed in a comprehensive, integrated and patient-centered perspective.