Investigation of notalgia paraesthetica using laser Doppler velocimetry and immunohistochemistry before and after treatment with topical capsaicin

Abstract

AbstractBackground Notalgia paraesthetica is an uncommon sensory neuropathy of unknown aetiology that appears to be mediated by peptidergic nerves.Objective To investigate both functional and anatomical aspects of notalgia paraesthetica using laser Doppler velocimetry and immunohistochemistry and to assess the effect of treatment on these parameters.Methods Basal blood flow and response to local heating were recorded in 7 patients with notalgia paraesthetica from within the affected area and the contralateral side as control. Biopsies were taken from both sites for immunohistochemistry with S100 protein. PGP9.5 and CD la. Measurements were repeated after treatment with topical capsaicin.Results All patients benefited from capsaicin treatment suggesting that the symptoms of notalgia paraesthetica are mediated by peptidergic sensory nerves. Basal blood How and response to local heating were generally reduced in the affected areas prior to treatment but this did not achieve statistical significance. These differences were less obvious following treatment. The density of CD1a immunoreactive epidermal Langerhans cells and small nerve fibres in the upper dermis both appeared to be slightly increased in the majority of patients within the affected area. No significant change was noted in 3 patients who were rebiopsied after treatment.Conclusions We conclude that in notalgia paraesthetica there is a localised functional abnormality of peptidergic sensory nerves. The relevance of the subtle histological findings is unclear.