Cutaneous sensory disorder.

Cutaneous sensory disorder (CSD) represents a heterogeneous clinical situation where the patient presents with either disagreeable skin sensations (ie, itching, burning, stinging) or pain (ie, allodynia) and/or negative sensory symptoms (ie, numbness, hypoaesthesia). These patients have no apparent diagnosable dermatologic or medical condition that explains the cutaneous symptom, and typically have negative findings upon medical workup. Skin regions that normally have a greater density of epidermal innervation tend to be more susceptible to the development of CSD. CSDs can affect any body region but generally tend to be confined to the face, scalp and perineum, and have been referred to in the literature with region-specific terms such as burning mouth syndrome, glossodynia and vulvodynia. Symptoms such as pruritus with unexplained hyperhidrosis may occur during sleep, as a result of heightened sympathetic tone. Sleep deprivation and insomnia can play a moderating role in CSD. Somatization and dissociation can play a central role in the pathogenesis of CSDs. A review of the literature suggests that CSDs represent a complex, and often poorly understood interplay between neurobiological factors associated with neuropathic pain, neuropathic itch and neurologic/neuropsychiatric states (eg, radiculopathies, stroke, depression and posttraumatic stress disorder). These neurologic/neuropsychiatric states can modulate pain and itch perception by potentially affecting the pain and itch pathways at a structural and/or functional level.