Notalgia paresthetica: a study on pathogenesis

Background Notalgia paresthetica is a sensory neuropathy involving the dors al spinal nerves. The characteristic symptom is pruritus on the back, occas ionally accompanied by pain, paresthesia, and/or hyperesthesia, which resul ts in a well-circumscribed hyperpigmented patch in the symptomatic area. Th e etiology of this condition has not yet been completely defined. Objective Possible mechanisms that could explain the pathogenesis of notalg ia paresthetica were investigated through clinical examination and various diagnostic tests. Methods Ten cases of notalgia paresthetica underwent dermatologic, neurolog ic, and orthopedic examination. This was followed by skin biopsy, electrodi agnostic investigation, and radiography of the spine. Results All patients had a typical symptomatology and dermatologic picture. Neurologic examination and standard electrodiagnostic investigation result s were normal in all cases. Histopathology was compatible with postinflamma tory hyperpigmentation; there were no amyloid deposits. In seven cases, deg enerative changes in the vertebrae were observed and, in all of these cases , these changes were most prominent in the vertebrae which corresponded to the dermatome of the cutaneous lesion. Conclusions The striking correlation of notalgia paresthetica localization with degenerative changes in the spine suggests that spinal nerve impingeme nt may contribute to the pathogenesis of this entity.