Neurogenic Cutaneous Sensory Dysesthesias
Central Nervous System
Neurogenic pruritus originates in the central nervous system without evidence of neural pathology, for example pruritus associated with neurotic excoriations (Weisshaar, Kucenic, & Fleischer, 2003). Otherwise unexplained pruritus may also reflect asomatoform dissociation (Gupta & Gupta, 2006). While antihistamines that are sedating such as hydroxyzine (Atarax®) or doxepin (Sinequan®) have some antipruritic effect, there is no really potent antipruritic medication available to treat this condition. In some cases, hypnosis and self-hypnosis may be helpful (Shenefelt, 2000).
Peripheral Nervous System
Examples of peripheral neuropathic itching include brachioradial pruritus, notalgia paresthetica, postherpetic neuralgia, and anogenital pruritus. Brachioradial pruritus is itching of the lateral distal upper arm, antecubital fossa, and proximal forearm, usually worse during the summer (Walcyk & Elpern, 1986). Peripheral neuropathic pruritus associated with cervical spinal foramen impingement may be the etiologic factor in some patients (Goodkin, Wingard, & Bernhard, 2003). Notalgia parasthetica is a neuropathic pruritus of the medial subscapular area that at least in some cases may relate to nerve impingement in a thoracic spinal foramen (Eisenberg, Bameir, & Bergman, 1997). Topical menthol or capsaicin may offer relief, as may oral gabapentin. Postherpetic neuralgia is a neuropathic pruritus, pain, or paraesthesia following herpes zoster (shingles). It occurs more frequently in individuals older that 60. Topical treatment with capsaicin, which depletes substance P, may be useful. Oral gabapentin may help reduce the neuropathic sensations (Eisenberg, River, Shiftrin, & Krivoy, 2007). Acupuncture and hypnosis (Scott, 1960) have been successful in relieving the sensations in some patients. Pruritus ani and vulvae may be neuropathic (Cohen et al., 2005) or psychogenic. Topical treatments with pramoxine and hydrocortisone may help some patients. Oral antihistamines may benefit some patients (Weichert, 2004).
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Cite this: Management of Psychodermatologic Disorders - Medscape - Jul 01, 2010.
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