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Brachioradial pruritus (BRP) and notalgia paraesthetica (NP) represent 2 of the most common neuropathic itch syndromes. A total of 58 consecutive patients presenting at the Center for Chronic Pruritus, University Hospital Münster, were analysed with regard to clinical presentation, anatomical and morphological pathologies, impairment in quality of life, and response to treatment with topical capsaicin. Patients with BRP reported stinging and burning more often than those with NP. In the BRP group structural magnetic resonance imaging abnormalities more frequently correlated with localization of the symptoms compared with in patients with NP. In addition, intraepidermal nerve fibre density was decreased in lesional skin in patients with BRP, but not in those with NP, confirming the neuropathic origin in BRP. Topical capsaicin resulted in a significantly higher alleviation of itch and pain intensity and improvement in quality of life in patients with BRP compared with those with NP, which may reflect clinical and aetiological differences between the conditions. [ABSTRACT FROM AUTHOR]

Prurigo nodularis ( PN) is a pruritic condition with altered epidermal neuroanatomy as demonstrated previously. Here we elucidated neuroimmunological mechanisms by combining functional, morphological and gene expression experiments in twelve subjects with PN and eight healthy controls. Subjects with PN showed a reduced intra-epidermal nerve fibre density ( IENFD) in lesional skin. Quantitative sensory testing indicated maintenance of somatosensory function compared to controls. None of the tested molecular markers including the neuron-distracting SEMA3A and neuron-attracting NGF were altered in lesional vs non-lesional skin in PN subjects. Accordingly, we speculate that scratching may contribute to reduced IENFD rather than an authentic endogenous neuropathy. [ABSTRACT FROM AUTHOR]