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

Abstract

Background Notalgia paraesthelica 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 veiocimetry and immunohistoehemistry and to assess the effect of treatment on these parameters.Metbods 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 immunohistoehemistry with SIOO protein. PGP9.5 and CDla. 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 tlow 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 CDla 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. S0926-9959(94)0()070-0 S.M. Hatpetn ct ai/J. Etir. Acad. Dermatoi Venereoi 7 (1996) 22H-234 229